Hello, I'm trouble shooting Parking Brake Indicator and Armrest Indicator Are Flashing on my CAT 226B serial number MJH08353. In the attached picture, in purple I highlight what I believe is the detent coil. I have two questions, first, is this the detent coil? It's located under my right hand control when in the operator seat. The second question is regarding the amount of resistance/ohms that this should have. I unplugged it and it's reading 53.1 ohms, is that the right amount of resistance for this part? I have also attached 3 other docs that I'm referencing while trouble shooting. In the RENR6419-06 - Electrical Schematic document, on page 8, it shows the Solenoid: Detent Valve should have 9.4 ohms of resistance. I'm just not sure if I'm looking at the right part due to different names like dent coil and detent valve. Thank you.
That is the detent coil circled in your photo. No idea where the "dent" comes from. You should have a 172-0970 coil installed at that location. The coil resistance specification is correct on the schematic, 9.4 ohms @ 25 DegC ambient. So if you measure 53.1 ohms that is not correct. Check the Part Number on the coil would be my first suggestion.
Thanks for the quick reply. The "dent coil" was a spelling error, I updated my previous comment to the correct spelling. I just removed the detent coil to verify the part number but it doesn't have any part number information on it. The wire seems like it's melted in spots like it got hot. I bought this machine used so I'm not sure if this was previously replaced. With no part number listed, I'm wondering if this isn't a CAT factory part or if the detent coil doesn't have a part number on it from the factory. Not sure where to go from here other than buying a new coil from CAT. Do you know if this part should have a part number on it?
I don’t I’m afraid. I think your best option is to buy a replacement. You could search online by Part Number and maybe get a genuine Cat one from eBay or similar, but TBH your only 100% guarantee that you are getting a genuine article is to buy one from a Cat dealer.
Okay thank you, I will see what I can find. Do you think that my current detent coil reading 53.1 ohms could be the reason that my parking brake and armrest indicator are flashing?
I wouldn’t have thought so, but anything is possible.
That's the electromagnetic coil for the boom float, I believe.
I just made it home from the Cat dealer and now I'm more confused. They had the detent coil part number 172-0970 in stock. The guy at the parts counter was nice enough to let me open and test the resistance on the part with my multimeter and it tested at 54.8 ohms. So what am I doing wrong? The docs say it's supposed to test at 9.4 ohms but I'm getting 54.8 on the new part out of the box. I'm very green on electronics and testing so maybe I'm misunderstanding something. Please help.
Is your meter off. Are you calibrating(zeroing) meter before using, right scale. the long and short is, there is nothing wrong with it.
I'm zeroing and I'm using this setting (see attached pic) on my multimeter. Is this the correct setting to test the detent coil?
I’m not sure what that particular setting is. Edit: I found the manual for your DMM. It’s an audible signal for continuity. I suggest that you turn one click clockwise to the “2K” setting and try again. See if the results change.
Thanks Nige, I just tested at 2k and I'm getting .051 From what I'm reading online, at 2K I would multiply .051 x 1000 = 51 ohms Am I understating this correctly? If this is correct, the new part at Cat was reading the same or very close to this so I'm confused on where 9.4 ohms is coming from for this part in the RENR6419-06 - Electrical Schematic document
I would suggest that you try measuring the resistance using a different meter. I looked in other places apart from the schematic and everywhere showed the same value for the resistance. Either all those sources are wrong, or your meter is potentially suspect.
I tested again with a cheap Astro AI meter I had laying around and the coil tested at 52.8 ohms so I'm not sure what's going on with the docs referencing 9.4 ohms. To make sure I'm testing the detent coil correctly, I'm simply unplugging it and testing continuity between the two wires on the coil, is that the correct way to test?
I'm looking at the attached doc for trouble shooting the armrest indicator is flashing. On step 17, it's saying the detent coil should be 12 ohms, not 9.4. Is there a newer version of the trouble shooting document or does it seem that there is different information on the resistance for the detent coil?
It says to check the wires of the coil, not the coil itself, if you read it. Did you do all the previous steps in your diagnostics?
Thanks Arny, when you say "check the wires of the coil, not the coil itself", I'm testing the two wires that connect to the coil circled in red in the attached picture. I should not be testing the wires circled in yellow that connects the coil to the harness, is that correct? At this point based on the results when following the trouble shooting steps in the Parking Brake Indicator and Armrest Indicator Are Flashing (RENR6417-01) and the Armrest Indicator Is Flashing documents it seems like I have an issue with my wiring harness. With that said, I'm concerned that I'm looking outdated/incorrect documents because the Armrest Indicator Is Flashing doc says the detent coil should be 12 ohms and the RENR6419-06 - Electrical Schematic document says detent coil part number 172-0970 should be 9.4 ohms. Can anyone clarify why the two documents are calling for different ohms on the detent coil?
Sorry, I misspoke, you’re doing it right, according to manual. But ya, according to manual, anything other than 12 ohms is faulty coil. But you’re getting the same reading on new one, correct? Did you do any of the other testing procedures, I glanced at them, and there are quite a few, for your issue. I wouldn’t sweat the 12 ohm vs 9.5 discrepancy. That circuit you’re testing is for the float, and I’m sure it’s 12v and ground. You can test with key on, and shove joystick forward, it should lock in place. Not sure if your aware of that.
No worries at all. Yes that's correct, I tested a new one out of the package at the Cat dealership and it measured very similar to mine. I'm familiar with how to put the machine in float mode, the only problem is that with the parking brake and armrest indicator flashing I can't get the machine or the bucket to move to test the float. It will start but the controls aren't working. I will mention that after leaving the battery disconnected then reconnecting, sometimes the machine will work fine but as soon as I lift the armrest and get out of the machine the parking brake and armrest indicator start flashing. I just went out and disconnected the battery, I will let it sit for a bit and then attempt to start it and see if I can test the float.
I think I asked already, but did you follow the procedure in RENR6417-01.
I have been following the steps in RENR6417-01, here are my results: Step 1. NOT OK - The armrest indicator is flashing and the parking brake indicator is flashing. Proceed to Test Step 2. CHECK THE RETURN SOLENOID WIRE FOR A SHORT TO GROUND (I'm getting OL. on my meter) NOT OK - The resistance is not greater than 5000 Ohms. Proceed to Test Step 3. CHECK THE HYDROSTATIC PILOT SOLENOID FOR A SHORT TO GROUND (I'm getting OL. on my meter) NOT OK - The resistance is not greater than 5000 Ohms. Proceed to Test Step 4. CHECK THE WORK TOOL PILOT SOLENOID FOR A SHORT TO GROUND (I'm getting OL. on my meter) NOT OK - The resistance is not greater than 5000 Ohms. Proceed to Test Step 5. CHECK THE WORK TOOL DETENT COIL FOR A SHORT TO GROUND (I'm getting OL. on my meter) NOT OK - The resistance is not greater than 5000 Ohms. Repair: The wire harness has failed. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. STOP Overall my meter is reading OL. on steps 1 - 5. I'm trying to find any rub points or issues with the wire harness but I'm not finding anything. I did try starting my machine again to test the float but it's still flashing the parking brake and armrest indicator so I can't get it to move. Do you have any tips/advice on what I can do from here?
When you did your resistance test, was your meter on the 20k setting?
I'm 95% sure I tested the meter on all of the resistance settings available. I will test again on 20k. When doing this test, the key should be off but the battery still connected, is that correct?
Yes key off. It doesn’t hurt to do tests over again, sometimes you miss things, first go. Follow along carefully.
Why would you expect to find anything on your wiring harnesses.? "OK" for each Step 1 thru 5 is defined by the test procedure as a resistance measurement of anything above 5000 ohms. Your meter is showing "OL" (Open Loop) or in other words "infinite resistance". That's way over 5000 ohms - infinite resistance in fact - therefore your results indicate that every one of those five steps was a "Pass/OK"
Okay, so based on Arny's comment, I tested again at 20k and got the same .OL results on steps 1 - 5. Nige, according to what you're saying, OL is "Pass/OK" on steps 1 - 5. With that information I moved on to Step 6. Here are my results: Test Step 6. CHECK THE CIRCUIT FOR THE HYDROSTATIC PILOT SOLENOID FOR A SHORT TO THE + BATTERY TERMINAL A. Measure the resistance at the wire harness connector from contact 29 (wire H416-GN(Green)) to the following contacts: contact 1, contact 11, contact 13, contact 24, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70. Expected Result: The resistances should be greater than 5000 Ohms Results: • OK - The resistances are greater than 5000 Ohms. Proceed to Test Step 7. • NOT OK - The resistance is not greater than 5000 Ohms on at least one of the readings. Repair: The wire harness has failed. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. STOP MY RESULT : On step 6, contact 24 is reading 0.01 on the 20k setting and .016 when I test on the 2k setting. I believe .016 on 2k equals = 16 ohms. Looking at the electrical schematic, it looks like contact 24 is the IMPL PILOT SOl. The repair says the wire harness has failed. Even though my results here are NOT OK, I continued with the test to provide more info. Test Step 7. CHECK THE CIRCUIT OF THE WORK TOOL PILOT SOLENOID FOR A SHORT TO + BATTERY A. Measure the resistance at the wire harness connector from contact 24 (wire 126-PK(Pink)) to the following contacts: contact 1, contact 11, contact 13, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70. Expected Result: The resistances should be greater than 5000 Ohms. Results: • OK - The resistances are greater than 5000 Ohms. Proceed to Test Step 8. • NOT OK - The resistance is not greater than 5000 Ohms on at least one of the readings. Repair : The wire harness has failed. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. STOP MY RESULT : On step 7, I got OL on all resistance settings. Test Step 8. CHECK THE CIRCUIT OF THE WORK TOOL PILOT SOLENOID FOR A SHORT TO + BATTERY A. Measure the resistance at the wire harness connector from contact 66 (wire 975-WH(White)) to the following contacts: contact 1, contact 11, contact 13, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70. Expected Result: The resistances should be greater than 5000 Ohms. Results: • OK - The resistances are greater than 5000 Ohms. Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the Test Steps again. Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". STOP • NOT OK - The resistance is not greater than 5000 Ohms on at least one of the readings. Repair: The wire harness has failed. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. STOP MY RESULT : On step 8, contact 13 is reading .008 on the 2k setting. I believe .008 on 2k equals = 8 ohms. Looking at the electrical schematic, it looks like contact 13 is the PARKING BRAKE SOL. The repair says the wire harness has failed. Even though my results here are NOT OK, I continued with the test to provide more info. Test Step 9. CHECK FOR A FLASHING PARKING BRAKE INDICATOR AND/OR A FLASHING ARMREST INDICATOR AFTER THE SYSTEM IS ENABLED Note: The seat will still need to be occupied and the armrest will need to be down. The key start switch will also need to be in the ON position. A. Press and release the parking brake switch. Expected Result: The armrest indicator and the parking brake indicator should be off. Results: • OK - The armrest indicator and the parking brake indicator are off. Repair: There is no problem at this time. STOP • NOT OK - Both indicators are flashing. Proceed to Test Step 10. • NOT OK - The parking brake indicator is flashing. Repair: See Troubleshooting, "Parking Brake Indicator Is Flashing". STOP • NOT OK - The armrest indicator is flashing. Repair: See Troubleshooting, "Armrest Indicator Is Flashing". STOP MY RESULT : On step 9, both indicators are flashing. Test Step 10. CHECK THE RETURN SOLENOID WIRE FOR AN OPEN CIRCUIT A. Turn the key start switch to the OFF position. B. Raise the cab. See Operation and Maintenance Manual, "Cab Tilting". C. Locate the interlock ECM. The interlock ECM is located on the left side of the machine beneath the access cover on the floor of the machine. D. Remove the wire harness from the ECM. E. Measure the resistance from contact 29 to contact 68 (wire H416-GN(Green) to wire 975- WH(White)) of the wire harness connector. Expected Result: The resistance should be approximately 11 Ohms. Results: • OK - The resistance is approximately 11 Ohms. Repair: There is more than one problem. Start by troubleshooting one of the fault indicators. See Troubleshooting, "Parking Brake Indicator Is Flashing" or Troubleshooting, "Armrest Indicator Is Flashing". STOP • NOT OK - The resistance is considerably greater than 11 Ohms. Repair: There is an open in the return solenoid wire. Check all connections. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. STOP MY RESULT : On step 10, I'm getting .009 on the 2k setting. I believe .009 on 2k equals = 9 ohms. Looking at the electrical schematic, it looks like contact 29 is the XMSN SOL. In this test, would 9 ohms be considered "approximately 11 ohms" as mentioned in the expected result? I'm not seeing a tolerance for this part so I'm not sure if 9 ohms would be considered approximately 11 ohms. My garage is cold right now at 31°F. I read that cold temps can decrease ohms, not sure if that is a factor for this though. Overall, based on the results it still seems that there is an issue with my wire harness. Any tips on how I should procced based on this new information?
Wow a lot of info to process. Other than visually inspecting harness, did you look around the main control valve? You could also use the audible setting of your multi meter, hooked up to the circuits you think you have a problem with, and wiggle the harness, listen for drop outs. A scope would work better, if you have one.
I know it was a lot of info, I apologize, I'm just trying to be thorough as I'm new to this. When you say main control valve, are you referring to the fuse panel or something with the hydraulic system?
Hydraulic. You can search this form for similar problem, if you haven’t done so, already.
I have read more posts on this form than I'd like to admit while trying to solve this lol. My next step is to find a mobile mechanic that works on Cat equipment to come out to my house and read the ECM and test the wire harness. Thanks for your input/information on this.
Let us know what you find, so we all benefit.
Thanks Arny, will do. I have a question on something I noticed in the RENR6417-01 - Parking Brake Indicator and Armrest Indicator Are Flashing document. On step 8 it says: Test Step 8. CHECK THE CIRCUIT OF THE WORK TOOL PILOT SOLENOID FOR A SHORT TO + BATTERY A. Measure the resistance at the wire harness connector from contact 66 (wire 975-WH(White)) to the following contacts: contact 1, contact 11, contact 13, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70. According to the Electrical Schematic, wire 975-WH(White) is wire number 68. Can anyone tell me if I should be testing contact 66 or 68 here?
Always use the information from the electrical schematic over whatever is mentioned in a procedure, which can be somewhat generic. The schematic (provided you have the applicable on for your Serial number) can usually be relied on to be correct. So the correct Pin in your case is 68, as per the schematic.
Thank you. My serial number is MJH08353. Looking at page 2 of the schematic under the electrical system for the 226B, I'm only seeing MJH1-10574. Do you know of a different schematic for 226B machines starting with MJH0 instead of MJH1?
No, because "MJH1" is Cat's shorthand for MHJH00001. The schematic you have is correct for your Serial Number, effectively from the first MJH machine built onwards.
Thanks for clarifying. So the only thing that is standing out to me right now is this: Test Step 6. CHECK THE CIRCUIT FOR THE HYDROSTATIC PILOT SOLENOID FOR A SHORT TO THE + BATTERY TERMINAL A. Measure the resistance at the wire harness connector from contact 29 (wire H416-GN(Green)) to the following contacts: contact 1, contact 11, contact 13, contact 24, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70. • NOT OK - The resistance is not greater than 5000 Ohms on at least one of the readings. MY RESULT : On step 6, contact 24 is reading 16 ohms. Looking at the electrical schematic, it looks like contact 24 is the IMPL PILOT SOl. The repair says the wire harness has failed. Does this seem like a wire harness failure or an issue with my implement pilot solenoid?
It would appear so, because in truth your meter should register "OL", or infinite resistance, between those two witres, not 16 ohms. Those two wires should not be in contact with one another anywhere on the machine. You can easily test the implement pilot solenoid. The Part Number is 195-9700 and I can see at least 4 others on that schematic of yours with the same Part Number. Do a switch of two identical solenoids and see what happens
I just lifted my cab to locate the other solenoids. Other than the two solenoids under the left and right controls that show as part number 195-9700, I don't see any other solenoids that match part number 195-9700. I do see these three solenoids, the two in the picture on the left side are part number 226-9629 (looking at Cat website, this part has been replaced with part number 323-9533) and the one on the right is showing part number 430-3612. When I search for this part on Cat website, I'm not finding anything. Looking at the machine location in the schematic, it looks like the two on the left would be location 8 and the one on the right location 39. Can any one confirm what these three solenoids are referred to as?
Referring to my last post here, can anyone tell me where the parking brake solenoid is for my machine? I'm thinking it's the one circled on the right in this picture but I'm not 100% sure.
I did more trouble shooting on contact 29 and contact 24. If I unplug the detent coil and the implement pilot solenoid, I can get the meter to read OL. If I unplug the detent coil, I get 18 ohms. If I plug the detent coil back in and unplug the implement pilot solenoid, I get 60 ohms. I'm having a hard time following the wiring diagram in the electrical schematic due to lack of experience. With that said, since the meter is reading OL while the detent coil and the implement pilot solenoid unplugged, I'm thinking it has something to do with the ground circuit in the harness. Could anyone please tell me if contact 29 and 24 share any other wires than the ground circuit shown in the wiring diagram?
That is the park brake solenoid valve. So the fact that you get OL with both solenoids unplugged and measureable resistance with them plugged back in again indicates that somewhere there is a connection between 975-WH (the common return wire for both those two solenoids AND for the Trans solenoid) and H416-GN, the power wire for the transmission solenoid. Really what you need is a Deutsch connector unpinning tool. See this LINK but you can also get them elsewhere. Note that these tools are fragile and easy to break if too much force is used. the 975-WH should be unpinned at Pin #4 on the joystick side of CONN 27, then repeat your tests. To do that the two halves of CONN 27 will have to first be disconnected before the 975-WH wire can be unpinned, then reconnected again.
Thank you so much this is very helpful. I actually do have that unpinning tool (bought it a few weeks back when I was looking for connection issues on the harness) so that is great news. I'm going to head out to the machine in about an hour to test this. Last night I found what appears to be a bad ground strap from the cab to the frame of the machine. Could this be causing the parking brake and arm rest indicator to flash? Or is this definitely an issue with the common return wire?
Put the ground right before moving forward, simply to eliminate the possibility that it is associated with the problem. It shouldn't be related, but you never know, and if you've found it - fix it. Before you go unpinning at CONN 27, take a good look at the LH joystick wiring. H416-GN & 975-WH are shown right next to one another in the wiring for the XMSN SOL, and I imagine that they remain in the same harness right the way back to the ECM. IMO it is more likely for wires to get damaged in a 2-wire harness than it is in one that has 20 wires.
Will do, thank you. I'm going to run to Cat right now and grab the new ground strap. When I get back I will install it then inspect H416-GN & 975-WH. If I don't see anything obvious there I will test CONN 27. I will follow-up with what I find. Nige I would be lost without your help. Thank you again.
Okay, I installed the new ground strap and inspected the LH joystick wiring. There were two zip ties on the wires, I removed the zip ties and it looks like there is a very slide indent on the white wire, (1st attached pic). I'm not sure if that could cause issues so I continued onto testing CONN 27. I unpinned pin #4 on the joystick side then reconnected CONN 27 (2nd attached pic). I repeated the steps on test 6 and got OL on contact 29 and contact 24. Does this mean I have an issue with wire 975-WH on the joystick side of CONN 27?
Did you reconnect either the detent coil and the implement pilot solenoid before testing.? If not then you need to do that because remember from before it is those two coils that make the connection to wire 975-WH between the RH joystick and CONN 27.
No, because you need a direct electrical connection between the two wires, not just damaged (but unbroken) insulation. Somewhere the insulation on both those wires has to be worn away leading the conductors inside to make contact with one another and cause a short circuit.
Hey Nige, I did reconnect the detent coil and the implement pilot solenoid before testing so we are good there. This makes sense. So in my previous pics you can see that I've already cut some of the insulation around the wire harness. Where the wires are exposed (no longer wrapped in the insulation) I don't see any wires that are worn away where the conductors inside are making contact with each other. Should I continue cutting the remaining insulation back to see if there are wires where the conductors are coming in contact? If the harness doesn't have any rub points, I wouldn't think that there could be wires worn down to the conductors but I'm new to this so I could be missing something.
I'm not sure if this changes anything as far as trouble shooting but I wanted to mention it. I just found that I can leave the detent coil and the implement pilot solenoid plugged in and get OL on contact 29 and contact 24 if I unplug the hydrostatic pilot solenoid.
i went out for a walk tonight and was turning this over & over in my mind. Disconnecting the hystat solenoid from the machine harness was going to be my next suggestion. When you measure the resistance between Pins 24 & 29 you are measuring from H416-GN to P988-OR. The only (although somewhat tenuous) connection between those two wires is 975-WH which is the common return from both the solenoids and the detent coil. The hystat pilot solenoid and the implement pilot solenoid are supposed to be the same Part Number according to the electrical schematic. Can you swap them over as a test without too much effort.? Leave the 975-WH wire disconnected from Pin 4 of CONN 27 for a start and see how it goes.
Before you do the above….. Measure the resistance of the hystat solenoid coil and then reconnect it to the machine harness. On the RH joystick unplug the detent coil but leave the implement pilot coil connected. Measure the resistance between Pins 24 & 29 of the ECM connector and report back.
Oh, and reconnect the White wire at CONN 27 before you test.
Thank you Nige. I'm out with the wife today but I will get back out to the machine tomorrow to test and follow-up.
I have the exact same issue on my ZSA machine right now.. 17 ohms from pins 24-29 at the ECM connector. Unplug the Hystat connector and it goes OL. Just now i unpinned the common 975-WH from the HYstat and plugged the connector back in and it stays OL. FYI
OK, here's the deal. The diagnostic procedure is WRONG - or to be more accurate some parts of Steps 6 and 8 are wrong. One always assumes that factory documentation is correct and sometimes this is a false assumption, as it is here. To figure this out it is necessary to refer to both the written diagnostic procedure and the electrical schematic RENR6419-06. Considering Step 6 first, it states - "CHECK THE CIRCUIT FOR THE HYDROSTATIC PILOT SOLENOID FOR A SHORT TO THE + BATTERY TERMINAL. Measure the resistance at the wire harness connector from contact 29 wire H416-GN to the following contacts: ..... contact 24" - I'm only going to concentrate on that particular one. It's not easy to follow the schematic unless you are familiar with them, but below is an abbreviated drawing showing the affected circuits. So if the 70-pin ECM connector and the detent coil are unplugged and the probes of the multimeter are on contacts 24 & 29, what exactly are you measuring.? Well follow the arrows........ From Pin 24 left along wire P988-A5 OR, down the orange link, left across P988-R11 OR, and you arrive at the implement pilot solenoid coil. Through the coil, right along wire 975-R13 WH, down the black link, left on 975-A46 WH, and you arrive at the Hystat solenoid coil. Through the coil, right on H416-A6 GN, up the green link, right on H416-A6 GN again, and you end up at Pin 29. So the resistance measurement on this circuit is the resistance of the two solenoid coils (disconnecting the detent coil will make measurements easier) plus maybe a bit extra for the wires, certainly NOT in excess of 5000 ohms (OL on the meter) which would indicate an open circuit.
Now to consider Step 8 where there is a text error......... "CHECK THE CIRCUIT OF THE WORK TOOL PILOT SOLENOID FOR A SHORT TO + BATTERY Measure the resistance at the wire harness connector from contact 66 wire 975-WH to the following contacts: contact 1, contact 11, contact 13, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70." However on the electrical schematic contact 66 is shown as wire G969-A13 YL which is the relay return. Wire 975-A14 WH is on contact 68. So by measuring from contact 66 to contact 13 you are actually measuring the resistance of the Park Brake solenoid coil. So the instruction should read - "Measure the resistance at the wire harness connector from contact 68 wire 975-WH to the following contacts: contact 1, contact 11, contact 13, contact 42, contact 47, contact 58, contact 60, contact 62 and contact 70."
Hey Nige, I reconnected white wire at CONN 27 then I measured the hydrostatic solenoid and I'm getting 9 ohms. It's about 40 °F here right now. When it's warmer, in previous tests I usually get 9.3 - 9.4 ohms on both hydrostat and implement pilot solenoid. I plugged the hydrostatic solenoid back in then unplugged the detent coil and tested pins 24 and 29, I get 18.3 ohms.
See my post #55 above. 2 x 9.3 = 18.6 or thereabouts. With the detent coil unplugged you are measuring the resistance of the two solenoid coils in series.
Thank you for putting that image together. I apologize as this is probably obvious at this point with the information you've provided but I'm having hard time fully grasping this. Where I'm getting the roughly 18.3 - 18.6 ohms does that mean both hydrostat and implement pilot solenoids have failed or that I have an open some where along 975 between the two? OR there is nothing wrong in this test and the diagnostic procedure is wrong.
As per my explanation in Post #55 above Step 6 of the diagnostic procedure is wrong - but only in respect of measuring the resistance between contacts 24 & 29. The rest of the other contacts mentioned in Step 6 are fine, and the resistance between any of them and contact 29 should register OL on your meter. You can prove the above if you reconnect the detent coil and disconnect the implement pilot solenoid and measure the resistance between contacts 24 & 29. The resistance should change from 18.6 to 9.3 + whatever is the resistance of the detent coil, 53 ohms was the figure I think you mentioned. So your meter should indicate somewhere around 62 ohms.
No it does not. In fact it indicates that they are both within specification, and the wiring harness continuity is good.
Got it, now I'm following. So the part that is confusing me is that when nothing is unplugged, when I measure 24 and 29 I get 17.8 ohms. I would expect to get somewhere around 73.3 ohms. I just went out and got new measurements now that the outside temp has warmed up. Measurements of both LH/RH solenoids and detent coil: - Hydrostatic sol = 9.4 - Implement sol = 9.3 - Detent coil = 54.6 Total 73.3 ohms resistance. When measuring contact 24 - 29 I get the following ohms: - Nothing unplugged = 17.8 - Hydrostatic sol unplugged = OL. - Implement sol unplugged = 64.4 - Detent coil unplugged = 19.1 - Implement and Detent unplugged = OL. Should I be getting roughly 73.3 ohms here or does the detent coil get bypassed in this resistance test when both solenoids and coil are plugged in?
Thanks for that info,I suspected the same when i compared the pinouts on the diagram to the procedure in test step 6.
No you should not. When resistances are wired in parallel (e.g. the detent coil and the implement pilot solenoid coil) the total resistance of that part of the circuit is NOT the sum of the resistances that are in parallel. The formula for total (equivalent) resistance when two or more resistors are connected in parallel is: - See this LINK So in your case it is 1 divided by (1/9.3 + 1/54.6). So 1/ (0.1075 + 0.0183). This works out to 1 / 0.1258 which equals 7.95 ohms. With everything connected you should measure 7.95 ohms + 9.4 ohms = 17.35 ohms which is not a million miles away from your measured 17.8 ohms.
Thanks Nige, you have been so helpful. It sounds like I'm passing step 6 since I'm getting OL on all other contacts. I moved to step 7 and got OL on all contacts. Same OL results on step 8 when measuring from contact 68. Step 8 tells me to stop here and that ECM is unlikely to have failed and to perform steps again. Any advice before I start shopping for ECMs? I've read (not sure how accurate) that technicians can't plug into the interlock ECM to read codes with a computer, only the (i believe it's called) auxiliary ecm for code diagnostics, is this true?
Cat ET can connect to the machine but there are no Cat Datalink connections to the Interlock ECM, only to the AUX hydraulic ECM. So I'm not sure if hooking up ET would do any good. I've never had the opportunity to try it on a machine of that vintage, only the newer ones where all the ECMs communicate via the Cat Datalink. I hate having to condemn an ECM. They don't fail often which is why the troubleshooting procedures always state that an ECM failure is "unlikely" and to repeat all the tests again.
Thanks Nige, I'm not ready to throw in the towel yet on the ECM. The thing that I'm curious about is that I can disconnect the battery for a few hours, hook it up again and run the machine just fine until I lift the armrest and get out of the seat, that's when the lights start flashing. Shouldn't the lights flash even after the battery has been disconnected, or does the ECM need some time to register after battery disconnect?
Steps 3 to 5 all state the same thing, they are simply testing a different component (each of the three coils) in each step. The procedure states "Expected Result: The resistance should be greater than 5000 Ohms." You are measuring OL on each of the three steps - or infinite resistance if you will. This measurement is far in excess of the 5000 ohms minimum value from the troubleshooting procedure. Therefore your results in Step 3 to 5 should be considered as "OK" . The problem is how the text is organized on the page which could be confusing to some people. Until you mentioned it I never took much notice of the detail - all I saw is "OK - the resistance is greater than 5000 ohms." and literally blanked out the rest of the text because I had all the info I needed. I have cut & paste the text below to show what it ought to look like in order to be more clearly understood. If the ECM is de-powered it effectively "goes to sleep" (it has no internal battery). This takes a certain amount of time to discharge any capacitors that might be in there. I have no idea what's inside the Interlock ECM TBH, I have never seen the inside of one. Generally you would reckon that 15 minutes should be enough to put any ECM to sleep. I think what's likely to be happening is that something inside the ECM is either heating up or suffering from vibration, so when you power it from "cold" having disconnected the battery it works fine. However when you change the state of some input into the ECM (such as the armrest switch) whatever is awry inside the ECM goes tilt and fails to work. It may even not be a failing/failed component, it might be nothing more than a soldered joint that has cracked. However it would need the services of a specialist ECM repair shop to test/diagnose/repair. This might interest you. It could be worthwhile giving them a call, but I would suggest that you get a price for a Reman ECM, Part Number 10R8097, before you contact them so that you can compare their repair cost & warranty to that of a replacement ECM
This really clears things up for me, thank you so much. I called Cat and they want $3300 for a reman ECM, IF my core is accepted. I will call the company you shared in the video. I found this https://www.ebay.com/itm/385713741761 remanufactured ECM on eBay. What are your thoughts on going this route? Do you know if the reman ECMs are plug and play, or do they need to be calibrated to my machine?
On the same page there is a Reman version of the same Part Number for $1000........ I would suggest to call the company in the video and get their prices before making a decision. There is no requirement for calibration AFAIK. Any ECM, whether new or Reman, ought to be plug & play.
As far a plug and play that is great news. I will call them now. Nige, I can't thank you enough for your help. The weight of this forum seems to be held up by your contributions. I will follow-up on how things go. Once I find the best price (either sending mine in for rebuild or purchasing reman) before moving forward on the ECM, do you have any additional advice on what I could test/attempt beforehand?
Those ECMs on eBay appear to be from a company based in China. AFAIK Cat ECMs are not manufactured in that country so there is a possibility that they are clones. I wonder how they expect to get your existing ECM shipped back to them as a Reman core.? I'll be interested to see what price ERD come up with to repair your existing ECM
I found another option here and figured id share it, i think i am going with this company as the turn around time is quicker than ERD. They are out of Texas and the website says 1-2 day repair time.. The only downside for me is my housings are severely corroded and had water intrusion and they cannot replace the housing. Module Repair Services Fast, reliable repair services for ECM, TCM, FICM, GPCM, and TIPM modules. Backed by a 1-year warranty and 24-hour turnaround. Save money by repairing instead of replacing. goecm.com
I called ERD and their price is $1600 to repair my ECM. I ordered the ECM from eBay and the company doesn't/hasn't mentioned anything about sending my current ECM back as a core. It's going to take about 2 weeks for my new (refurbished) ECM to get here.
I have the same problem. My housing is in bad shape so I went with the refurbished one on eBay.
That would have been good information to share right at the start. It throws suspicion on the ECM straight away. Also you would not have received Core Credit from Cat for an ECM with a corroded housing.
Agreed, I wasn't aware of how bad it was until yesterday when I removed it. I couldn't (didn't bend down far enough) see the bottom of it when it was installed in the machine while I was testing. On another note, the eBay seller did reach out to me asking for a picture of my serial number on the machine and a picture of the current interlock ECM. I wonder if this is so they can bench program it or if they are simply checking that I ordered the right one to avoid a return.
I'd be wary of giving them a photo of the whole data plate. I would supply a photo of just the last 8 characters (MJHxxxx) which is all they should need to confirm that the ECM is correct for your machine.
Good to know. Can they do some type of scam with the whole data plate?
Potentially. The 9th character (3) of the PIN immediately before the Serial Number (4) is referred to as a "check character" to make it harder to clone a PIN plate. Supposedly only the factory knows what it is for any specific machine.
Interesting, thanks Nige. When I get the ECM installed I will follow-up with the results.
I wanted to follow-up on this thread. My ECM got here a lot faster than I expected but I installed it and it doesn't work. My machine won't start and there are no lights on for the parking brake or arm rest. Any tips or suggestions would be wonderful. As of right now, I'm in the process of returning the item to the seller.
Dead battery, Battery switch off. When it comes to electronics, I try not to mess around with aftermarket or rebuilt stuff. IMO their never as reliable as original. I believe this is were the phrase Pay to Play came from. Another reason the correct diagnoses is critical, or things add up in a hurry.
Battery is good, I put my old ECM back in and it started fine but continues to have the issue with the parking brake and armrest flashing. I wish I could afford to buy the ECM from Cat but I can't. I was hoping I was missing something after installing the new one but the install seems straight forward so I think the new/refurbished one from eBay is bad. I don't have to do any type of reset or anything like that when installing a new ECM, is that correct?
It is. The "software" in your Interlock ECM is hard-wired into a replaceable EPROM chip that plugs straight into the motherboard of the control. If with your old ECM the engine would start but the problem was the flashing alarms allied to the park brake not releasing, but with the replacement ECM the engine won't even start then the replacement ECM is obviously bad - QED.
I figured the replacement was bad. Thanks for confirming.
I want to keep up on this thread as I gather new information. I took my machine to CAT and they plugged into my Aux ECM with CAT ET. Here are the results: Long story short I picked up my machine and CAT didn't perform additional work on it. Can anyone tell me if the Logged or Active Diagnostic Codes could be the culprit to my issue with the armrest and parking break indicator flashing? I know the interlock ECM is tied to the Armrest/Seat switch but I'm not familiar with these status reports (i.e. the differences between logged and active codes) so any additional info would be appreciated.
Quite simple. An Active Diagnostic Code means the Code is there right now - Active in other words. A Logged Diagnostic Code means that the Code was Active at one time but is not Active at this point. Therefore it is Logged in the ECM memory. Attached the troubleshooting procedure for 1184-3. Let us know how you get on.
Will do, thank you.
Hey Nige, after following these trouble shooting steps here are my results: Step 1. - I'm getting .OL on all contacts. Step 2. - I'm getting 0.00 volts. According to the trouble shooting procedure my ECM has failed. My question is surrounding both ECMS at this point. It seem that this test is testing the Aux ECM but at the beginning of this thread, I was originally trouble shooting the parking brake and seat belt indicator flashing relating to the Interlock ECM. During the trouble shooting for the the parking brake and armrest indicator flashing / Interlock ECM, we discovered that there are inaccuracies in the trouble shooting (see post #55 ) so I want to make sure I'm not missing anything. Should I trust the CAT ET and replace the Aux ECM or the previous trouble shooting and replace the Interlock ECM? OR maybe both have failed? This seems unlikely but I'm not sure at this point. To summarize, I'm still dealing with the parking brake and armrest indicator flashing and the machine won't move. From my understanding and what we spent time trouble shooting, these are tied to the Interlock ECM.
I'm struggling to understand the test procedure TBH. Need to read up on it a bit more. I'll get back to you on that. A question. Do you use the AUX Hydraulics on your machine for a clamshell bucket or other attachment requiring AUX hydraulics.? If not then I would suggest to focus your attention on the Interlock ECM for the moment.
The 1184-3 code was active when the Product Status Report was downloaded from the ECM. It also shows that same code logged 100 times in the last 100 hours. In other words it's intermittent. If you're getting 0.00 volts between 42 & 3, and you can see that 1184-3 code active within ET simultaneously , only then would I suspect the ECM. You need ET connected to diagnose that properly. Without ET connected it's hard to tell. The interlock system reports to both ECMs... Based on the above, certain pins need to be grounded and certain pins need to be open. The source is the 202 ground wire. Make sure that's good first. If the whole system is bypassed, and you still have your armrest light on, well that's most likely an ECM fault. Which one will be the next thing to determine. And ffs, if you bypass anything, make sure is goes back to how it was after testing. This is how people die.
Sorry for the delay, I've been out of town. The machine has the connection for the hydraulics but I've never used them. Here is a picture from the diagnostic from CAT. The wires have been like this since I've owned the machine and it was working so I didn't pay much attention to it. Maybe this is the reason for the 1184-3 code?
Do you have a better photo.? it's hard to see much detail. TBH though I can't see problems in that connector causing an issue with the circuit for the AUX solenoid valves.
I don't think it does either because the connection that is missing for these wires would leave them open like they are now Here are some better pictures:
The damaged wires seem to have been insulated/isolated from one another pretty well. I can't see that throwing any spurious Codes.
Thanks for the additional information. Do you have any input/trouble shooting steps on how I can go about testing the 202 ground wire?
The only thing I can suggest is under NO circumstances use the resistance function of your DMM. In the circumstances where the 202 wire could literally be “hanging on by a thread” it might well show acceptable continuity but will be incapable of passing any significant current. I would suggest to disconnect the wire at both ends (or at multi-pin harness connectors) then supply battery+ voltage at one end then connect the other end to machine frame ground via a 5A test light. If the wire will pass 5A without melting it’s in good shape.
Okay got it. I was able to borrow a power probe from a friend to supply + voltage. Sorry if this is an obvious answer to this question but I need to ask. I have a cheap 6v/12v test light, according to the owners manual the test light has a 12v/3w bulb and a 20amp clamp. Will this test light work or is the 5 amps going to blow the bulb? If needed I can go get a different test light.
No it will not. 5A at 12v is 60W which is a bit different to 3W. The whole idea is to get a decent current flowing in the wire so that if it is in any way dodgy it will pop. TBH all you need is an automotive lamp holder with a 60W incandescent lamp in it and a couple of wires soldered to the lampholder. See first few seconds of this LINK . Disclaimer - I would solder the wires to the lamp holder rather than just twisting them like he did, but hey ho........
Oh that's cool. Okay, one more question on the bulb. I have a 55w halogen in the garage, would that do the trick or do I specifically need a 60w incandescent for this test?
A 55W halogen would work. TBH you don't need a power probe, just some suitable lengths of wire to connect Batt+ to one end of the 202 Black wire, your lamp, and a piece of wire to connect the other end of 202 Black to frame ground if you are testing it to some intermediate point. If you propose to leave 202 Black connected to ground at one end then basically all you need is a long enough length of wire to connect Batt+ to the lamp and another short length to connect the lamp to the exposed end of 202 Black. Simples.........
Okay thank you. Before I continue with the test light I wanted to go out and locate wire 202 and I'm not finding it. At the arm rest connection I'm seeing a black wire, 200-cn139. In the electrical schematic it's 202-cn139. The ground that contacts the cab near that location has three wires contacting it. 200-cn32 203-cn125 203-PA127 I'm not seeing 202. Maybe there is a different electrical schematic for my machine? Here is a picture of the three wires going to the ground. You can also see the connection to the armrest on the left.
Believe the schematic. 202--CN139 goes right from the armrest switch to the cab ground in Grid H-11. Personally even if the 55W lamp lights fine I would be tempted (after having done that test not before) to disassemble the wires at the cab ground point and clean all the ring terminals, then reassemble. While you are in there check the connection on the other end of the 7G-1060 cab ground strap is clean and tight.
Before I move on with testing the armrest switch with the test light, I wanted to mention this and get some clarification. The other day when I was going through the troubleshooting procedure for 1184-3, I had the wire harness for the Aux ECM unplugged in order to troubleshoot. After I followed the steps I never reconnected the wire harness to the ECM. The following day, I went out to move the machine so I could pull my trailer out of the backyard. I forgot I never reconnected the wire harness but I was still able to start the machine with the Aux ECM harness unplugged. After I had started the machine and moved my trailer I realized I had forgotten to reconnect the harness. So my question is, how did the machine start with the Aux ECM unplugged from the harness? What is the purpose of the Aux ECM?
Its full title is Aux Hydraulic ECM, which gives a clue as to its function. There is nothing in it that would prevent an engine start. That is the function of the Interlock ECM. I'm assuming that although you started the engine you never attempted to move the machine or operate the implements.?
Okay got it. I started it, raised the bucked and dumped water out because it had rained and the bucket was full of water. That's when I realized the harness was unplugged. Should I have been able to raise the bucket with the Aux ECM unplugged?
Yes because your machine is old style with pilot-operated implement controls, not the electro-hydraulic joysticks used on later C & D models. The implement lockout switch is an input to the Interlock ECM. The only systems that are electro-hydraulic on your 226B are the controls that require push-buttons and/or the thumbwheel roller to operate.
Okay great, thanks for clarifying. I will follow-up once I use the test light on the armrest switch.
I finally found time to go test this. I'm not sure I tested it correctly though. I started by disconnecting my battery from the machine. I then connected my test wires, on one end of batt+ and batt- to my battery on the machine then I connected batt+ to the test light and the arm rest connection, black wire 200-cn139. Then I connected batt- to test light. The light obviously turned on since it had batt+ and batt- from the machine battery. The black wire 200-cn139 did not get hot but I don't think that applies due to how I tested it.Do I need to leave the battery cables connected to the machine during this test? To clarify, I don't have 202-CN139 on my machine at this location. At the arm rest connection I have black wire, 200-cn139. The ground that contacts the cab near that location has three wires contacting it. 200-cn32 203-cn125 203-PA127 Any advice on how to test this the correct way would be appreciated. I'm sure your instructions above make sense and I'm just missing something.
First the test light. 1. You should disconnect both the Batt+ and Batt- cables from the battery. They remain disconnected throughout the test. 2. Connect a temporary wire from the Batt+ terminal to the test light. 3. Connect a temporary wire from the other side of the test light to one end of the wire you want to test - 200-CN139 at the seat end in this case. 4. Connect one end of a temporary wire to the other end of 200-CN139 (when you find it). Touch the other end of that same temporary wire to Batt- The test light should light if 200-CN139 is in good shape because you are passing the current powering the test light (approx 4.5A) through it. Question: How many ohms of resistance do you measure on the 200-CN139 wire between the seat switch and machine frame ground.?
Perfect thank you! Any advice on how to locate the other end of 200-cn139 since it's not showing 200-cn139 in the electrical schematic? I'm thinking I will need to remove the cover from the wire harness and follow it until I find the end. For the resistance measurement on 200-cn139, (see pic for how I tested) I disconnected the armrest switch and left the seat switch connected. Then measured from 200-cn139 with the red probe and the black alligator clip attached to the machine ground. If I tested it correctly I'm getting 0.00 ohms on that test.
I would suggest that you do the test again and this time set your meter dial on the 2k ohm setting rather than the 20k setting that it's on in your photo, just to see if it makes a difference.
Okay, just ran out and tested at 2k and got .000 I'll work on locating the other end of 200-cn139
That measurement sounds implausible. There should be something even if it’s only decimals of an ohm. Unless it’s a reflection of the accuracy of the meter you are using.
I tested this yesterday, the light turned on (see pic) and the wire did not get hot. I found that 200-cn139 ties into 203-cn125. 203-cn125 is the ground to the machine frame. Following your instructions above, I connected batt- temp wire to 200-cn139 and batt+ temp wire to 203-cn125 and the test light. After the test, as recommended I removed the grounds an cleaned them and the contact to the frame. I'm guessing that I didn't test this correctly. When you say the 200-cn139 wire between the seat switch, should I be testing the G985-CN137 wire on the seat switch connection? Previously I tested 200-cn139 from the arm rest connection to the machine frame.
From what I can see the ground connection from the armrest switch appears to be fine. i think maybe the level of accuracy of your meter is not sufficient to register the (v small) resistance that would normally be measured between 200-CN139 at the armrest switch connector and machine frame ground. Also by using the 55W lamp to pass current through 200-CN139 and the wire does not get hot I think you can safeyl say it's in good shape. You can test both G984-CN58 and G983-CN138 using the test light & temporary wires from the armrest switch to the ECM. In the case of the latter it will be via the seat switch (where it morphs into G985-CN137) so you will need weight on the seat to close the contacts of that switch.
Hello, I'm still working through this issue with my machine when I have time. I needed to move my machine yesterday so started it up and moved it. While doing that, I noticed that the detent coil was not working. I shove the joystick forward and it would lock for a second then unlock. I wonder if my detent coil is causing all of the issues that I'm having with the parking brake and armrest indicator flashing. Any one have any thoughts or input on the detent coil being the culprit? Thank you!
Hey Nige, I did these test and everything seems fine. I sent my ECM to GOECM and they said it couldn’t be repaired due to corrosion. I purchased a refurbished ECM from them. It arrived yesterday and I installed it. When I turn the key on I get a battery and oil light but the machine won’t attempt to start. Do you have any ideas on what could be going on? Did I get a faulty refurbished one from GOECM?
No I don't have an idea. It should be plug&play. I think you may have a bad ECM but better to refer back to the supplier for advice before condemning it.
Nige, I ended up sending the ECM back to GoECM for a second replacement. The second one arrived today and this one seems to be working! I can't thank you enough for your help. I learned a lot about electrical trouble shooting while I was working through this issue. Thanks again!
I went back and forth with the issue before convincing myself it had to be the ECM that was causing the trouble. But with no way of testing it apart from knowing that it SHOULD work when connected to the machine how can anyone really tell.? As the old say goes, "you can have cheap or you can have good, but you can't have both at the same time." When you go non-OEM you roll the dice every time you buy.
Agreed! GoECM does have a lifetime warranty so that makes me feel better about purchasing through them. There was no way I would have figured it out without your help. Thanks for sticking it out with me until we found the issue!
Great thread. Did the Interlock ECM end up fixing this particular issue?
Hi, yes it did!
Was your ECM better or worse to the one I pulled out of my 287b?
The bottom/backside of the housing on mine was really bad. I couldn't see it until I pulled it from the machine. I pulled the back off of mine to inspect it and it was clear that the electronics were corroded.
First, thank you all for this troubleshooting thread. Update, performed all this troubleshooting to know fix until the last resort of replacing the interlock ECM. The flashing lights have stopped but I’ve yet to work the machine for the final test. Thank you all again.
Buenas tardes estimados, ¿la falla se solucionó reemplazando la bobina? Tengo el mismo problema, si la desconecto a la bobina el equipo comienza a funcionar... cual es la función de esta bobina?
Welcome. To comply with the forum rules you will need to post in English. Please start with a machine Serial Number.
Hello, I had a similar problem on a 226B2 skid steer loader (MJH04220), the parking and armrest indicators were flashing. In my case, it was not the ECM that failed, it was the faulty retention coil. When the coil was disconnected, the equipment began to operate normally. I left the retention coil disconnected in order to operate the equipment until the new part arrived.
Very interesting. Can I ask which coil are you referring to.?
The coil I am referring to is located on the right joystick, attached photo.
Ah, that is the one for the implement handle detent. If you go back to somewhere around Post #55 on Page 3 the subject of that coil was discussed.
Apologies to the seniors here. This my question (moments ago) to a similar but different thread. I have an early (2000) 226 SN# 5FZ03535. Troubleshooting Interlock issue similar to this thread. Flashing seat and park light. After it starts- and i push park brake switch, both lights flash. Current SIS2Go subscription and I’m confused by the wiring schematic vintage nomenclature. Attempting to identify the wiring diagram for my machine. Advice?
I noticed that Nige got you taken care of with the wiring diagram in the hydrostatic pilot solenoid thread. Good luck trouble shooting!
I had the same issue with a 2003 226 and it ended up being my detent coil, once unplugged the machine no longer had interlock issues. i believe my machine is earlier than what was described in this thread so the trouble shooting procedure must not be exactly the same since some of it didnt make sense. I have not yet replaced the solenoid. my dealer current shows $343 for the 172-0970 part
Post your machine Serial Number. That will indicate if the troubleshooting procedure here is applicable to you.
Hello, it seems to be normal for the retaining coil to fail. Lately, my clients don't replace them; we simply leave them disconnected, so we can work without any problems. Besides, they're not cheap to buy every time they fail.