Hello all, I arrived at job site this morning to find my auxiliary switch no longer powering my grapples on my cat 287b Just appears to have gone dead. Let me give a brief history of events leading up to this problem. Last year my machine began malfunctioning when the seatbelt light kept flashing and not allowing me to operate my controls. After constantly turning machine on and off it would work again. This went on for a few days before this trick no longer worked and my machine was stuck. It started fine, but hydraulics would not work as seatbelt light would not stop flashing. I replaced safety switch and had an auto electrician out but we could not find the short to ground that seemed to be the cause of malfunction. We ended up wiring solenoid so directly to fuse box this overriding the safety mechanism. This turned out to be a hugely dangerous mistake when I nearly lost my arm a month ago by accidentally leaning on joystick when my arm was under the skid steer arms, but that is another story. Anyway, machine has worked fine, but then in order to operate grapples I was always having to start machine, and then hit the park brake button before auxiliary switch would allow flow. This was not a problem, but all of a sudden today my park brake light no longer comes on, and auxiliary rocker switch no longer energises solenoid. My engine seems to have trouble starting also but we think we have narrowed that down to a loose relay on the fuse board. Has anybody got any ideas? I am hoping it is not a problem with computer as they are not the easiest things to access. Also, I am West Australian so my local CAT dealer is booked out for the next 5 years with all the mining machinery. Thank you in advance for any help you can offer.
My apologies, Initial problem was not park brake, but the seatbelt light flashing.
Do you think an electrical schematic would help your auto electrician diagnose the fault..? If so then send me a PM with your machine Serial Number and your email address. If you want a full copy of the diagnostic procedure posted by Mobiltech in the other thread just let me know.
Hello, I took the Cat 287b to the dealer yesterday. He calls back saying the inspection cost me $600 and to fix was going to cost me $3680 as it was a fault "in one of the ECM's". I told him to jam it basically and I will fix myself. I also asked for a quote on both undercarriage replacements , $18000 each!! Is it any wonder Westrac is laying off staff, no one in their right mind would take a machine to be serviced and repaired by these thieves.
Where is that solenoid? I'm having the problem you described with my skidsteer. I can start the engine, but the hydraulics won't work and the seat belt light flashes both when the engine is dead and the engine is running.
Can anyone tell me where the seat belt flashing light solenoid is on a 236B?
It is not a seat belt flashing solenoid, it is probably a fault in the interlock circuit. I would first check the magnetic safety switch under the rear right hand side seat harness, make sure it is working with multimeter. Then check the switch underneath the seat. If the machine won't start when you are not seated then the seat switch is working. If you want to run your hydraulics, get some electrical wire and join the solenoids under each joystick to any live fuse in the fuse box. This is a temporary measure to move machine, DO NOT continue to operate in this form as eventually you will lose a limb! If you are unfortunate like me, it will be the ECM that is at fault, (apparently very rare) , they are approx $800 to buy, or you can hand over $3900 to a dealer to put in.
This skidsteer is old enough to have come over on the Mayflower, so first off the seat switch was wired around, so it's not the problem. I'm a rookie at this electrical diagnosis, too. I was tinkering with it all day yesterday, started the thing at one point and voila! the seat belt warning and parking brake lights had stopped flashing and the doggone thing moved, so I have absolutely no idea where the problem was. I'm sure it's a short somewhere that my rustling around had stopped. Now I can't trust it to start and run any time. Thanks for the response. I may have to do that at some point.
Yes mine did this also, I used to turn key off and on and everything would work again. It started to get progressively worse and at times I took as long as 10 mins flicking ignition back and forth before it would work. Then the day came when it would no longer work. As I have fond out, mine was the ECM, but you could get lucky and find a short somewhere.
Please be careful with the machine in that condition. Be aware that if you are working on the machine with the engine running and inadvertently operate a control or if something goes wrong with the pilot system and operates a function even without your input you could easily end up DEAD. That switch is there for a very good reason. If you want an electrical schematic then please send me your machine Serial Number and your email address. I'll gladly send one to you.
Hello, I have a cat 287b high flow and cannot get a power rake with no electrical attached to it to work with my machine. Can someone help me with the procedure and testing.
Hello, I take it that means your auxiliary flow is not working? Ie no oil flowing through the outlet and return coupling on left arm when you use the roller toggle. If there is flow, you have a problem with your rake. If no flow, the problem is with either the solenoid, failed switch, or the Auxiliary ECM under the floor.
Thanks, I'm new to this particular machine. How do you start the flow, and which sokenoid is it, someone said its a couple things to do to get it flowing. Can't afford service manual!
Hey, The solenoid is on the right hand side of machine when you are sitting in the seat, or the left hand side of the machine if you are standing in front of machine with cab raised. You have to undo those 2 big bolts that are holding the cab down, once removed you can raise the cab up and gain access to the mechanicals underneath. I never bothered to put the bolts back, as I always wanted quick access. If you use your roller toggle on right joystick and you don't hear the auxiliary flow and the engine bog down a little, you probably have a failure somewhere. This happened to me, and it turned out to be a failed joystick and 2 failed ECM's. A very rare occurrence, and expensive I might add. If I were you, I would undo the plug that supplies power to the solenoid and attach a 12 volt power source to it and see if it functions (while engine is running of course). If you hear motor bog down, then solenoid is fine, and the failure is likely the joystick or ECM. I was a total newbie like you, but just give it a go, it takes a lot of time, but you will get to know the machine much better by doing things yourself. Keep asking questions and I will try my best to keep sharing as much as I know.
hi, could you post serial number PLEASE does the machine have the optional XPS hydraulic system? Mark
Hi, B1 B2 and B3 series are different so just guessing with this one(no S/N)but to enable high flow see below check last line description Mark
Thanks guys, sn is 0287blzsao2911. Still haven't figured it out. I have found hydraulic lockout switch is bad, but that is it so far. It is driving me crazy. The small hydraulic lines work, just not the big ones for a power rake. It is too wet to work here so it is in my shop with can up if y'all can keep the ideas coming. What color are the wires to the sokenoid, and yes it is an xps
Ok, have tested all solenoids and they make motor bog down. Also realized two speed isn't working, don't know if it's related.
Hi, could you clear up a few things please. which quick couplings are you hooking into, with xps there are three sets of couplers see photo below, if you are using the outside couplers they both connect into the same adapter (single pipe from pump)so maybe the couplers are not opening when you connect them together(incompatible couplers)these are operated by your thumb wheel if you are connecting to the middle couplers they are operated by the two button's on right joystick next to thumb wheel(joysticks change with different options) from memory the MTL loaders don't have two speed ????? maybe an option I don't know about there is also a switch in left hand upper console that has the standard /high flow option 1-electricial connector 4-Aux 2 coupler high flow 5- Aux 2 coupler standard 2-Aux 1 coupler high flow 3-Aux 1 coupler standard 6-C- connector 7- C+ connector 8- return to tank joy stick 1- thumb wheel 2- C- button 3-C+ button regards Mark
I'm having a very similar issue, although I have some addition 'weird' functionality that accompanies the auxiliary hydraulics (right joystick thumb rocker) not working: 1/ The fault comes and goes... 2/ When it is stuck with the fault the bucket is also stuck in auto level mode and I can't deactivate this using the auto level rocker switch (up on the top left console) 3/ The hydraulic pins for engaging/locking the attachment also don't work when its stuck in this state 4/ Other auxiliary hydraulics still work (these are the small lines typically for opening/closing the gate on the forestry mulcher) - I believe these are hydraulic lines 6 and 7 above. 5/ And as per the thread the bucket wont open and close (or if I have mulcher on it wont turn)...ie rocker not working When the auto level disengages functionality returns as normal. I have found in the past that this can come and go by turning the machine on and off and fiddling with the park brake. Its not necessarily linked and might just be coincidence. In the past while I've been using the machine the fault has disappeared and the thumb rocker begins to work all of a sudden after operating it for some time... I have also been using the machine with no issue annd 5 mins later after getting back in (turning the machine back on after its been running fine) this fault occurs. I'm not aware of any lockout with the seat belt...since I've owned the machine I have never used the seat belt. Is there a lockout on the seat belt? Any ideas, or an electrical schematic would be handy. This is frustrating. The interconnection of the faults makes me think that its something related to the ECM. But then it makes me wonder how the computer can fail unless its hardware on the ECM.
Machine Serial Number would be a good start ...... finding an Electrical Schematic isn't hard once we have that.
cat0287bkzsa01752
hi Kepler, Going by the symptoms that you describe the aux hydraulics , coupler pins and the bucket level system not working correctly. I would suggest you check the power feed to the fuse box containing the aux ECM fuse and the coupler/ level fuse they are fed by the same power wire which in turn is fed by power relay C as shown below Mark to confirm power issue .try your wiper washers when the fault occurs as they are also fed from this circuit sorry posted this before s/n was posted I may have to double check the sch lay out regards Mark
Perfect. As you said, had a look at power relay C and noticed the contacts were bent in a bit. Testing the really there was no fault and power at the pins was right. So I corrected the contacts to ensure there was proper contact being made. With that we had full functionality. Much appreciate you assistance here Mark.
glad I could help Mark
Nige, we are having a similar issue today. Washed the machine and the only thing not working is the thumb rocker. We have no flow and the engine doesn't bog down. Our SN is: ZSA03281 It was working all morning. Please advise
Nige, we are having a similar issue today. Washed the machine and the only thing not working is the thumb rocker. We have no flow and the engine doesn't bog down. Our SN is: ZSA03281 It was working all morning. Please Advise
Nige, Mark 250 - 256c XPS High Flow s/n DWS00524 First -Thanks guys for all you time and effort answer these questions. I am a fairly new Skid steer owner/operator, so the learning curve has been steep. My machine is new to me and has about 2000 or so hours, starts and runs fine and I have change all fluids etc to get familiar with it and typical maintenance. I have been looking online at available manuals to understand all the bells and whistles. My issue is getting the machine to work in high flow (to operate a forestry mulcher). Seem to run standard flow fine (open front mega mower). On occasion I get a couple green indications on the left top panel, one is continuous flow indicator and the other I am not sure (a green arc enlarging from left to right). I bought a connector cap for the aux. elec. that enabled continuous flow. Then heard I need a aux elec. cap for high flow. Can you clarify what is required to set the high flow up to run continuously and what indication you should have in the cab that it is in fact in high flow. Thanks again for your time.
hi PopArcher,to enable high flow on C series machines a connection must be made across pin numbers F and G at the connector on lift frame this is usually done via the work tool electrical circuit see below or post number 16 above to enable cont flow hold the cont flow button 6 below and operate the thumb wheel to its full extent then release button 6 and within 2 seconds release the thumb wheel this should enable high flow with the indicators in overhead panel lit up
Mark250, Thanks for the info. If all you mentioned is executed, should both the green indicators remain lit while operating? I had to install a dummy cap to get the Continuous Flow to lock in as you describe. Now, I understand the high flow jumper is required as well. I purchased a "high flow dummy cap" as well. They maybe one in the same? I will verify connections as F to G in both caps, to understand what I have in hand. I have ordered an Operations/Maintenance manual as others have said it would answer all these type questions and be a good resource for future issues. Thanks for your time. Wait I reread and understand they should be lit while operating. Thanks
hi, you don't a dummy cap for cont flow. it will work with standard or high flow. the indicator on the left in the circled item above is high flow and the other one is cont flow and will be lit when these options are selected Mark
Understood Mark, Thanks. I may have an issue then as mine would not run in continuous mode until I installed the 107$ dummy cap on the new aux plug in, the old one was crushed when I bought the machine..?? And the high flow indication will not stay lit. I am headed to the farm for the next week and will get to work with it some more. Thanks again for your time. Will update you with progress or not..
Mark250 , Nige - Closing the loop here - Continuous and high flow are now operational thanks to this thread and conversation. I found a bad connection in the Aux. Elec connector, as it had been crushed and I replaced the same and installed the dummy cap, thinking all was well. I just did not think I had to go there again, but as discussed here and many threads. The talk of short circuits and open circuits due to worn wiring harnesses etc. being the culprit of many problems, I went back and found an issue. Those darn pin extractor tools need some work.. one pin and it happened to be F was slightly miss shapened and not making a solid connection. Thus causing intermittent connections and correct operations on occasion. With High Regards Thanks
It's worth your while getting hold of a set of Deutsch connector pin removal tools. Each different wire diameter needs a different tool. They make getting pins/sockets out of connectors a breeze. Problem is that they are plastic and don't last long. http://www.deutschconnector.com/products/deutsch_connector_tools/deutsch_connector_removal_tools/
Timber2Tinder, I am having the same issue you described in your post. Did you ever figure out the problem?
nige funny aye? if two speed and aux are not working look to the common denominator of these two. They may both be controlled by the aux controller if its the same as the 257b. Just spent too much time on the same issue on a 257b.
Good morning, Very similar issue with my 2006 287B XPS VZSA03585. When I connect the auger attachment, I have no response when activating the thumb rocker switch. I have put 12V on both solenoids while machine is off to see if they at least actuate, and can hear the "click" when applied. Did a basic review of relays and fuses in the fuse block below the seat and all appear to be functional. Is there another check to complete that can rule out a CPU board or the thumb rocker switch itself? Any help is appreciated.
Start with the thumb roller switch. At the 12-pin harness connector directly below the joystick you should have 8v between Pins 1 & 2 of the connector with the key ON. If the 8v is good, then measure the output voltage on Pin 3. It should be somewhere around 4.5-5.0v with the roller in the centre and about 0.8v difference from the centre voltage when the roller is moved full forward or full back.
I have an older 287b CTL not the high flow model or enclosed cab model. It has manual attachment locks. My aux thumb control was working fine on my grapple attachment. I then removed it to rebuild the tilt cylinders. When I put it back on I could not get the aux to function with the thumb roller switch. Then after a while I got in and adjusted the old taped up seat cushions and sat down hard and suddenly the thumb roller worked!! It worked for several days and then it suddenly stopped working. I am wondering why everything else, lift, tilt, etc works perfectly but not the aux on the thumb roller? Is there anything to be looking at before the thumb roller switch itself?? My serial number is: CAT0287BPZSA03483
Have you looked at the condition of the electrical connectors on the AUX ECM down in the footwell.?
Not yet.... I will do that! Thank you sir! I'm retired and just use this CTL for around my small farm. So just trying to get some information as to how to approach fixing this issue.
There are two ECMs, one on each side. It might pay you to take a look at the connections on both of them.
Thanks Nige! It was raining hard so all I had time to do was pull the fuse cover and blow off all the dirt. I tried it after that... it did not seem to work, but then after a few minutes it started working again. doesn't feel like its the roller switch. When I have a chance I will lift the cab and trace the wiring, clean everything and make sure the connections are all good. Maybe it is just that simple. time will tell. Thanks again.
Update on my 287B. Buddy identified 8V not present at the thumb roller, so he started back tracking and got to the CPU module under the throttle foot petal to find what you see in the pictures below. Anyone know of a good supplier for these units, new or remanufactured? Hoping that this is the cause of my issue.
That would not be acceptable for a Reman core because of the corrosion. Check your messages.
I finally found the time to dig into the dirty belly of my 287b! Everything is cleaned up after about five buckets of mud, sticks, leaves, etc. I would like to know if there is a special reason why Caterpillar located both the ECM's down under the floorboard in the very bottom of the front part of the machine??? Since my machine is an open cab with no A/C I have plenty of room to relocate the units up to the left size under the cab where it would be easy to access in the future. They would be easier to keep clean and the harness looks plenty long enough to allow it. What do you think??
Unless you are an electrical guru with the capability of successfully & reliably modifying the wiring harnesses I would suggest you leave the ECMs right where they are and just make sure you clean the area on a regular basis. When you went into that area to do diagnostics I’d bet you were the first person to see them after the guy who originally installed them at the factory.
I would say you are right about the first person to see them....from the amount of dirt built up around them!! I think I could easily relocate them without changing the wiring harness at all. Just simply using the existing slack available there is enough length to remount them without modifying the harness. I'd still fasten the ecms directly to the main frame of the machine, but they'd be up where no dirt or moisture could easily get to them. The moisture down where they are located I think is the biggest threat to their integrity. I just want to be sure there is not some other factor as to why they were located way down there in that awkward spot.
Just figured I would give my feedback on what happened when my aux hydraulics were not working (thumb roller switch inoperable). Friend of mine traced issue back to one of the two ECM's under the floor board which had obvious corrosion and decay inside it (very poor location design). Ordered refurbished/programmed ECM from Yernparts.com and all is working properly.
Thanks Drew for your input!!! Mine is now working but has been hit and miss several times in the past. I'm still thinking about moving the ECM's to a better location since there is enough room and I would not have to alter the harness. It is not the most expensive part on the machine, but still costs enough to protect it as much as possible from moisture and corrosion.
See if you can find some of this stuff which works wonders keeping condensation out of electrical connectors. https://sensontek.com.au/product-details/electroguard-dielectric-grease-50g-tube
Yeah I had same issue. ECM. They are in terrible location. Every time I wash my machine I’m scared water will get in and short them out again. I paid $3k for them years ago.
Unfortunately I can add my name to the list here. I bought a used 287B 2 years ago in the hopes of using the Aux controls extensively. The guy I bought it from said everything worked except that the overheat light was low level coming on with the buzzer being annoying. He had a new OEM sender that he hadn't put on that he gave me, which I switched out, but didn't solve the problem (more questions on that later). Since the skid was operated by his hired guys, I don't think the owner was up on the latest information either. The pilot valves were leaking on both joysticks causing a wet cab, which I didn't like, but that's a used outfit. The Aux controls have always been intermittent for me. I could get them to work eventually by working the thumb wheel over, but it was definitely not good and not sustainable for the long haul. Last fall I replaced the pilot valves and the right joystick as the electrical lines were soaked in hydraulic oil and I didn't know if that was causing my intermittent fault. That also didn't solve the problem, so I replaced the solenoids as well. Still not working and in fact has stopped working all together. I have OHMed all of the wires from the solenoids to the ECM and they appear good. I've also replaced what I'm assuming is the common ground wire split connector to the solenoids and the Deutsch ends at the solenoids. Still no joy. I was very happy to find this thread, so yesterday I tried everything suggested in here with no solution but with the following results: jumper at the door connection working. 12 pin joystick connection is providing 8V at pins 1&2 to the new joystick Both solenoids will click under external 12V on either polarity. A few days ago the overheat light came on fully as soon as you turn the key as bright as it can with loud buzzer and will not go off. I'm suspecting a full short somewhere in the wiring, but I don't know if both of these problems have a common connection or not. S/N *CAT0287BTZSA02994* I'll welcome any help I can get from here.
You appear to have fired the Parts Cannon in the worst possible way without the benefit of any data-driven diagnostics to point the way for you. For example the pilot valves could have been resealed much more cheaply rather than replaced. It's not hard. If the AUX function worked occasionally it's hardly likely that the solenoids on the control valve were bad. Anyhow, on to the thumbwheel. Was the replacement joystick handle you installed a new genuine OEM one.? If yes, then check the output voltage signal measured between Pins 2 & 3. Measure the voltage with the thumbwheel in the centre position, rolled fully forward, and rolled fully back. Report your findings. While you are at it, apply battery voltage to each of the two AUX solenoids on the implement control valve with the engine idling. Does the AUX function work consistently (engine RPM lugs down) when you do this.? Regarding the "overheat" light, can you confirm that it is indicator #2 in the illustration below that is flashing. If it is, then go to the coolant switch on the engine and unplug the 2-pin connector. Does that silence the alarm.? If not, install a jumper across Pins 1 & 2 of the machine harness connector and try again.
It is number 2 on the illustration and it's no longer flashing it's just on. All parts up till now have been OEM. One follow up question on the solenoids. On a tractor, the hydraulic remotes must work in tandem with one being pressurized and the other being released in order to enable the flow. Do the solenoids on here work in the same manner? Or is it the case where one is activated and the hydraulic oil automatically flows out the other end and both solenoids are activated separately and singly depending on the direction of the thumb wheel?
Not exactly. The two solenoid valves actually only provide a pilot supply for the AUX control valve spool located inside the main implement control valve body. It is the AUX control valve that sends the oil to the quick couplers. So when either one of the solenoids are activated, supply pressure is sent to one or other of the AUX quick couplers on the LH side of the lift arm and the line from the other coupler is automatically opened back to tank. In the illustration below A1 and A2 are the two solenoid valves, the AUX Control Valve is the one in the rectangle.
That makes sense... Ok, pin 2&3 voltage: center 4.0 down 6.22 up 1.88 Both solenoids at idle do activate the spool with an outside 12V source and load down the machine.
OK, that's all good. The only thing to do now is to check that the voltage remains the same measured between the same 2 wires (P996-GN & P997-BR) at the AUX ECM end. That is located under the floor of the RH side of the cab, you will have to lift the floor to gain access.
Actually there is one step more remaining. When you complete the test above, turn the key OFF and unplig the 70-pin connector on the AUX ECM. You will need two cables for this test. Connect one between Pin 42 (wire L998-OR) and machine frame ground, then connect batt+ to Pin 40 (P978/A1 solenoid) and listen for the click. Secondly apply batt+ to Pin 58 (P979-YL/A2 solenoid) leaving the ground in Pin 42. Again listen for the click.
Ok... the voltages were the same at the ecm on the P996 and P997 as they are at the joystick plug. The second test was also successful. I was able to unplug the 70 pin and make both solenoids click from that direction, only PIN 40 has a much weaker click. Also PIN 40 GN felt a bit loose so I swapped it out with a new Deutsch female connector. The bad news? Started it up and we could get it to load up one time, but it didn't release fully until we turned the key off and back on again, then we could hear a large clunk. It never would cycle again. But underneath the floor panel in the old dirty oil/sludge, I found a fuse like jumper which has the same symbol on it as what the owners manual calls the diodes (37 & 38 in the fuse box). I also notice that Relay 35 is for the ECM signal for the Auxiliary Hydraulic C+ and Auxiliary Hydraulic C-. Neither one of the diodes in the fuse box have anything in them... Do they need to be jumped in order to work the solenoids? Or do the A1 and A2 not require anything in the fuse box...
A1 & A2 work direct from the AUX ECM. The only thing that is required is switched power to the ECM and correct inputs from any other switches (e.g. armrest). How about a photo and maybe identify some wire colours/numbers that are connected to it.? Is it this one by any chance.? A green, a black, and two grey witres. That is for the engine shutdown circuit. If it is as dirty under the floor as you imply then I would suggest a good general cleaning first, followed by a detailed of the AUX ECM connectors both on the machine side and the ECM side would be a good idea.
It's not that dirty... just down in the well. The ECMs are fairly clean. Those are the symbols I'm referring to.
Fuse 16 in the panel is labeled as auxiliary hydraulic ECM, could it be a sketchy fuse connection or maybe the ground wire on the ECM not making a good connection? Everything going to the ECM from the joystick checked out and from the harness to the solenoids... otherwise I'm guessing it's the ECM itself.
That's what my suggested testing was designed to establish. The only thing that makes me pause for thought is the fact that Pin 40 had a much weaker click than Pin 58. It might be an idea to swap the two solenoid valves A1 & A2 (complete valve not just the coil) and see if the weaker click noise follows the solenoid or stays where it is. Question: When you got the AUX function to engage and it wouldn't disengage until you turned the machine off was that sending a signal to the solenoid that is giving the weaker click.? I suppose at this point it's worth asking the question how clean is the hydraulic oil and when was the filter last changed.? Is there any remote possibility that particles circulating in the system could have got into the spools of the A1/A2 solenoid valves.? It most certainly could be. It will probably require thw "wiggle test" on the AUX ECM power & ground for a start. You can follow that up with the same test on any wire that brings an outside signal to the AUX ECM. i can see at least half a dozen wires that could affect the A1/A2 output if their signal to the ECM was interrupted for whatever reason. Let's not condemn it just yet. If you go OEM they are expensive, like $3k, to replace. So a fair bit of due diligence is called for before condemning it. A quick comment regarding the diode bridge you found. I don't think it is anything to do with your machine. C+ and C- are for High Flow machines only and your machine is not equipped with HF. Therefore it will be missing the relay #35 and both diode bridges #37 & 38 because they are not required.
I haven't got the quote functions here quite figured out yet so bear with me... The AUX function that engaged was when the roller was scrolled down. I'm not sure which solenoid that sends the power to. The weaker click was concerning to me also because when I activated both A1 and A2 from the outside 12V source they were both equal in sound and with the engine running at idle they both loaded down the machine equally and released when I broke the connection. That also sorta eliminates the probability of debris in the spools. It's almost gotta be something unique to the #40 pin and wire because it was not hooked to the ECM when I did your last test and it's a straight shot to the A2. What I guess I can do is make a new wire and replace the green wire from pin 40 back to the A2 and see if the click is as strong as the A1 signal up the yellow wire. At least then I can see if it's something unique to the wire itself or perhaps that end of the common ground (orange) didn't make a good connection at the splitter and I need to work on that. I'll also test out and see if I'm getting full power to the ECM through the fuse panel, I'm guessing it should be a full 12V. I'll also clean up the ECM ground wire and bolt head to make sure it's getting a good ground onto the frame. I can also test out how much voltage I'm getting at the solenoid connectors through the ECM when I roll the thumb wheel... I'm guessing they also should be a full 12V when activated.
Don't bank on it. TBH I'm not 100% sure. They could be proportional to a certain extent but even when the thumbwheel is rolled fully over they may not receive full system voltage because of losses. On a machine the age of yours it would not be surprising to find a harness that is squashed or damaged somewhere. Finding the problem is the hard part. Try following the harness from the ECM to the solenoids looking for any obvious signs of distress or damage. I'm not sure how visible it is over the full length. Try testing that one wire by disconnecting the 70-pin connector at the ECM and the 2-pin connector at the solenoid. If you connect one end of the wire to machine frame then supply batt+ to the other end via a fused 5A test light and it flows 5A it should be good. On the other hand when you ask it to flow 5A it may just go pop......
I just went out and checked... full 12V (12.36 to be exact) getting to the ECM, and it's fully grounded from what I can tell. There isn't a harness in between the ECM and the solenoids, just the three wires. Might be 4 feet long at the outside. I also tried to play octopus and test the voltage at the A1/A2 connectors while rolling the wheel... I couldn't measure any output at all, but I'll try again tomorrow with another set of hands and see if there's any change. If there's not... I'm not sure why there's no output through the ECM to them.
But tere has to have been, at least once in the last day or so, when you stated that rolling the thumbwheel beckwards actually engaged the AUX function. It comes down to one of two possibilities in the end; wiring or the ECM. One will be cheap to fix, the other won't.
I know what I'm hoping for... But I also know what I'm betting on. This is sounding very much like what one of my pickups was doing last year... new ECM.
If the worst happens there are options other than OEM, and at much keener prices as well.
Alright... I swapped out the wires from the ECM to the solenoids, other than the common ground being brown now... everything is wired the same. BUT, instead of having the girl in the cab (through no fault of hers), I climbed in instead and tested things out, and have found a slight change in conditions, I'm hoping that helps further diagnose the problem. I used the thumb roller and had no success either forward or backward. Then I pressed the trigger and boom it loaded down and didn't want to release, so I played with the trigger and it released. Then I tried the roller again and nothing, but pulled the trigger and tried the rollers and randomly the system would load down in either direction of the roller, but quite randomly. Sometimes the trigger needed to be held down, other times just clicked to engage then disengage. The book says the right hand trigger activates pin B on the Aux Electrical control (which has never had anything connected to it), but it certainly seems to be interfering with my AUX thumb roller!
That's weird, because the trigger has no input at all to the AUX ECM. Pressing the trigger connects wire 549-PK to ground. That pulls in the coil of RELAY 1 in the fuse box and sends power to Pin B of the 8-pin Work Tool connector on the side of the lift arm. The thought is crossing my mind that you may have an unknown number of wires in the harness between the 12-pin connector under the RH joystick and the AUX ECM shorted to one another.
Yes... I can believe that. Someone ahead of me has already removed the loom and it's wrapped in black tape to the ECM. I'll spill all that and make sure there are no wires shorted out. I'll chase that all the way to the joystick plug if I have to... I'll even look at the back of the fuse box at RELAY 1 to see if something got crossed back there somehow.
I suppose the appropriate comment at this point would be “assume nothing”. Is there any indication to suggest that this machine has ever been involved in a fire.?
A reasonably good test for potentially shorted wires within a harness is to set your multimeter to the ohm scale and connect a probe to one wire in the multi-pin connector. Then touch the 2nd probe of the multimeter to every one of the other wires in the connector in turn. Cat's spec is that the resistance between any two wires must be in excess of 5k ohms. Personally I prefer to see the meter reading "OL".
I unwrapped the harness and chased out all the wires I could. The four wires from the joystick that go directly to the ECM are in perfect shape. No blemishes or crimps or splices. The two wires that go from the joystick into the main harness (red and black) I kinda lost after they went into the loom. At least one has to be the trigger wire going to Relay 1, but I haven't broken down the fuse box to look behind the panel yet. I'm not sure what the other wire would be. Also... I can see this is a long time problem and nobody else has been able to adequately diagnose it either. Wrapped up in the tape around the wires were the initial green, yellow, and orange wires from the initial install of the AUX still in the Cat loom. Both ends of all the wires were snipped and taped back, but it's easy to see they were the originals that were replaced by the wires that I just replaced. That tells me this has been happening since the inception, and nobody else has figured out the problem either. They've done the exact same things I have culminating in replacing the wires to the solenoids. Unfortunately it's still my problem now. I'm wondering if somehow disconnecting RELAY 1 by either pulling the relay, or figuring out which wire is the trigger wire and disconnecting it from the joystick might do something productive.
Another possibility from before your ownership is rodent damage.
You have the schematic. It's not difficult to figure out which two wires are connected to the trigger by the pin numbers on the 12-pin connector under the joystick.
It was the red one... So I pulled the relay out and tried the AUX wheel only to have nothing happen. Then I pulled the trigger and still had nothing happen. So I put the relay back in and tried the roller to have nothing happen, and played with the trigger to once again have nothing happen... Now it's not even working intermittently so I guess I solved that problem! I've tested the signal wires coming into the ECM again and they tested about the same (4.0 base and +/- 1.2 either roller direction), then we started the machine and ran it at idle and I tested the outputs to the solenoids at the ECM end and had no voltage at either wire when activated. It's almost got to be the ECM. So... cheaper alternative you say?
I think it's got to that point, although I wish I could be more certain considering all the home-brewed modifications to the wiring. that always makes me nervous. Check your message inbox.
At this stage, it needs to be working...
Has anyone else here on the forum ever successfully brought an AUX hyd ECM back from the dead by re-flashing it? I'm all ears at this point...
And now the exciting conclusion... Went aftermarket ECM... fixed the problem.
I suppose the only consolation is that, through all the testing you performed, a defective ECM was the only logical conclusion even though the fix was not cheap. Many others would have simply thrown parts at it and ended up spending far more than you did.
Unfortunately if you'll go back to my first post... I already did that a year ago. In my defense, this forum was obviously so far buried in the search I did that I couldn't find it until the posts from last fall brought it back to the front of the search page. I sincerely appreciate all of your help in chasing out the problem. Not knowing what's wrong was more frustrating than paying for the actual fix. I'm quite discouraged that I got to know this skidsteer as well as I have over the last month, but at the same time I'm quite happy that I know this skidsteer as well as I do over the last month. In this quest I discovered at least 2 more unknown problems that I was able to repair that would have popped up eventually out in the field and shut me down a helluva lot further away from the shop. I've still got at least one repair ahead of me on a bogie wheel that was broken when I got it, but it's not vital to how I'm going to be using it like the aux was. All told it was still cheaper than an upgrade and hopefully with the limited amount of use I'll be putting on it (I raise cattle, not construction or landscaping), should last me a very long time in the future. Thanks again for taking the time to help a stranger out in a time of need.
This was the last time we exchanged dialogue. I had not had a lot of time to work on my 287b machine because of too many of life's other distractions! Anyway. I had the one ECM labeled Auxiliary sent off to ECM Engineering in FL. The tested and cleaned it and sent it back saying it was fine. I installed and the crazy grapple/solenoid function worked for a short time and then stopped again. So I figured it was in the thumb rocker switch and I ordered a new joystick from Holt Cat here and installed it. Nothing happened. I then called a local heavy equipment mech who came out and checked that the thumb switch was getting the correct voltage, and he told me the solenoids must be bad. So I ordered two new solenoids from Holt Cat. Installed them and still nothing. I had the mechanic back out and he traced all the wiring from the joystick to the ECM and the solenoid to the ECM and said the problem was in the ECM. So then I discoverd that the two ECM's datalink between the two and that the impulse from the joystick goes into the auxiliary ECM part#216-0658 and the signal to the solenoids comes from the Operator Interlock ECM part# 154-4233... so.... I sent both ECMs to ECM Engineering in FL to test and repair as needed. They found that the power supply in the Operator Interlock ECM had a problem that had damaged resistors in both ECMs. They repaired them, programmed them to their proper parameters and sent them back. I installed them, the machine started up no problem, the brake light which before had been flickering worked perfectly with no flicker....but still no solenoid function from the thumb rocker switch. Not sure where to go nexts except to bite the bullet and call out an official CAT mechanic. Do you have any ideas of what I should try next?
Go back to basics I would suggest. I assume that I must have sent you an electrical schematic at some point.? Please confirm. 1. Locate the 12-pin connector under the joystick and unplug it. Key ON. Measure the voltage between Pins 1 & 2. It should be 8.0 +/- 0.5v. Key OFF. 2. Reconnect the 12-pin. Key ON. Measure the signal voltage between Pins 2 & 3 with the thumb roller in the centre, then with it rolled all the way forward and rolled all the way back. Report the 3 results. While you are doing the above I suggest that you familiarize yourself with the wires and pin positions of the AUX ECM, especially the ones that take the output voltage to the A1 & A2 AUX solenoid valves plus the wire that is the input for the thumb roller switch signal. TBH I think your interaction with the outside repair shop was a waste of time. Attempted repairs to these ECMs generally don't work, at least not for long anyway. You would have been better investing the same amount of cash in new replacement aftermarket units from somewhere such as yearnparts.com
Not correct. There is no datalink, only four signal wires (G984, G985, E918, & F780) that supply signals from the armrest switch (both NO & NC terminals), the parking brake switch, and the implement lockout switch to BOTH the Operator Interlock ECM and the AUX Hydraulic ECM.
Again incorrect. The power supply to the A1 & A2 AUX solenoid valves comes from Pins 40 & 58 of the AUX Hydraulic ECM with the common AUX solenoid return on Pin 42 of the same component.
Thank you sir! As usual you are on top of what I need to check out. Yes. you did send me the schematic so I can follow the wire numbers and colors to their connections. I will take it step by step as I have time and report back what I find. If I get too lost in it all & can't fix myself, I'll just get a hold of a Cat specialist and pay to get it fixed.
Just take it one step at a time. As a result of the tests you do it will become obvious what the problem is. A couple of other questions:- Does the armrest up/down switch light work ok.? Not flashing or anything like that.? Ditto for the parking brake warning light. Does the machine in general work correctly apart from the fact that the AUX Hyd system doesn’t function.?
Yes. Everything seems correct apart from the no function of AUX Hyd. I may not have time to get back onto it till this weekend. After I do some of the tests you recommended I'll report back what I discover. Thanks!!!
I think I have been looking at the wrong wiring chart. The one I have is designated for CAT 287b ZSA1-up. My model is the standard flow open ROP serial number: *CAT0287BPZSA03483* So I believe I need to be using the chart for the earlier model. And that is why the numbers and colors sometimes are not making sense.
"ZSA1-Up" is Cat shorthand for "from first machine built" so therefore it is 100% applicable to your Serial Number. If the numbers and colours are not making sense I suggest you check whether the wiring is original or not. If it is original then you are not reading the schematic correctly. Question: Are you interpreting the colours that are drawn on the schematic as being wire colours.? If you are then confirmed you are reading the schematic incorrectly.
Thanks for clarifying that for me!! I will not be so concerned then with the colour of the wire and more with the pin locations I am testing.
You should be concerned. Provided that any wire is original the colour of that wire should absolutely match the colour shown on the schematic. Also each wire has a number printed on the outside of the insulation about every 6” along the length. BOTH the number and the colour should tally with what is on the schematic. There are several notes on the schematic that explain this. I suggest that you read all of them carefully before continuing your diagnostics. Try the bottom of page 12 and towards the bottom RH side of Page 13.
Thanks!!! That is what I am doing.
Okay. I finally had a chance to do what you outlined. Please forgive my lack of knowledge...electrical is not my strength. I checked the voltage at the joystick 12 pin connector. The "Key-On" voltage of pins 1 & 2 was 7.92 volts. ** that I reconnected & "key-on checked the thumb roller voltages between pins 2 & 3. It was 3.13 volts at center, 4.78 volts rolled down, and 1.47 volts rolled up. I next checked the continuity of wires from both solenoids to the corresponding pins (#40, 42,& 58) on the 70 pin connector at the Aux ECM. It showed no break in the wiring. I'm not sure what to check next. I think maybe see if there is voltage to the solenoids with the key on.... I'm thinking I may need the machine running with brake off. The other thought I have is to test the signal from the thumb roller to the ECM. Not sure which pin to check or what exactly to look for. Would that be pin 53 proportional signal? What is the method for checking? Do I test between pins or to ground? Thanks again for steering me in the right direction!!!!
Your supply voltage to the thumb roller switch is good. The roller switch output is a bit on the low side but it is varying correctly when you roll the switch in both directions away from the centre. Next step is to measure the voltage on the same two wires as they input to the AUX Hyd ECM. That will be on Pins 52 & 53, the same two wires P996 Green & P997 Brown that you measured at the joystick connector. You are looking for identical voltages (1.47, 3.13, & 4.78) to the ones you measured between Pins 2 & 3 at the joystick connector. Again, like the joystick end, you will have to measure these by back-probing with the 70-pin electrical connector for the ECM plugged in.
Okay. I probed the voltage between pin 52 and 53 with the 70pin connector plugged into the ECM with the key on and are the readings: Thumb-roller at center reads 4.07 volts, roller down 6.27 volts, and pushed up 1.852 volts. Not identical to the previous readings but more or less in the ballpark, maybe?? What do you think?
I’m happy enough with those numbers. They prove that the that is same voltage leaving the joystick is also reaching the ECM. Now unplug that same 70-pin connector. We’re going to try applying power direct to the AUX 1 and AUX 2 solenoids. This will test both the wiring harness integrity and that of both solenoid coils. Identify the following pins: - Pin 1 (Batt+). Wire 128 Pink. Pin 42 (Solenoid Source). Wire L998 Orange. Pin 3 (Ground). Wire 203 Black. Pin 40 (A1 solenoid). Wire P978 Green. Pin 58 (A2 solenoid). Wire P979 Yellow. You will need two short jumper wires. Start with the key OFF. Connect one jumper between Pins 1 and 42. It will stay there for the whole test. Step 1. 1. Connect the second jumper between Pins 3 and 40. 2. Turn the key ON. Can you hear the A1 solenoid click.? 3. Turn the key OFF, then repeat Step 2 a couple more times. Confirm that you can hear the solenoid click ON and OFF as you move the key from OFF to ON and vice versa. Turn the key OFF. Step 2. 1. Connect the second jumper between Pins 3 and 58. 2. Turn the key ON. Can you hear the A2 solenoid click.? 3. Turn the key OFF, then repeat Step 2 a couple more times. Confirm that you can hear the solenoid click ON and OFF as you move the key from OFF to ON and vice versa. Turn the key OFF. Report your results.
Thanks! I will get to that probably tomorrow a.m. & then get back to you!
Okay, The test from the 70 pin connector jumpered as you instructed showed between 3 & 40 key on "CLICK" sounded in one solenoid. And between 3 & 58 key on "CLICK" sounded in the other solenoid. I assume that that is good news. BTW the solenoids are brand new from CAT. Thanks a million! WHAT NEXT?
The results of all the tests prove that the correct signals are reaching the ECM from the joystick and that both the wiring and AUX solenoids on the output side of the ECM are fine. The conclusion is that you wasted your money on the ECM “repair” because it’s not working.
It has to be the Aux ECM then. The outfit gave a warranty, so when I send back and demand they fix it right... I can say that either Pin 40, 58, or 42 are not working properly. If they cannot repair... I'll follow your advice and get a good aftermarket replacement.
Personally I wouldn’t tell them anything apart from the fact that you have checked all the ECM inputs & outputs related to the AUX function and they are all working perfectly. Let them figure out what’s wrong with the ECM. Let’s face it they are allegedly the experts. As I think I mentioned earlier if you go for an aftermarket ECM try yearnparts.com https://www.yearnparts.com/catalogsearch/result/?q=216-0658
I really think you're the expert!!! And Thank You! for bearing with me on this. I'll report back after I get an ECM that works!! Best wishes!
HI again expert! I did not have to purchase a new aftermarket auxiliary ECM. The guys at ECM Engineering came through.... of course it was the third time I sent it to them. This time after installing the rocker switch is getting signal to the solenoids and it is working good! Thanks again for walking me through the steps to know where the problem was. I hope finally I can get some work done with this machine! Best regards to you!!