Hi. I have a 05 cat 277b. It is stuck in park on my trailer. Both lights flash. The parking light and the arm rest indicator. I tested all the solenoids and they are good. I pulled up the plate under the foot pedal and removed the harness from the ecm. I checked contact wires 3 to contact wires 68. (201-BK and wire 975-WH) and it says it should be greater than 5000 ohms. I just get OL. I am thinking one of those is a dead wire. I have a schematic in from of me but am trying to figure out where it leads to so I can check else where. Any tips? Thanks
What schematic do you have..? A genuine Cat one or a "will fit"..? A Cat schematic should leave you in no doubt as to where each wire goes. To get the correct schematic a Serial Number would be nice.
Hi, I am looking at this schematic, the last page. Says volume 2 of 2. The serial number is CAT0277BEMDH02115
Why do you think I'm getting ol?
5000 ohms or greater is CATs way of saying no connection between contact 3 and 68 which is the battery negative to the common return wire. O/L in multimeter lingo means open circuit
Yea that is what I'm looking at. Where does the contact 3 lead so I can check for a open in that wire and then I could check for a open in the ground wire (contact 68)
If you look at the interlock ECM on Page 2 of the schematic all the wires that come out of it appear to go into a thick vertical black line, including 201-BK & 975-WH. That line indicates a common harness. If you follow that line downwards a tad you will see a slightly thinner horizontal black line, again a common harness. That goes into another thick vertical line, etc, etc, until it finally ends up at a 12-pin connector (Grid ref G-3 on Page 2 of the schematic) marked "CONN 8". There is a note next to the connector that gives 2 alternate locations on Sheet 1 schematic where the other side of CONN 8 will be located. In the "Attachment & Cab Connector Locations" table located on Page 3 of 4 there is a key that details the machine location for each connector. According to that CONN 8 is located at #34 which appears to be somewhere behind the operator's seat. Hope that helps.............
contact #3(black) is a ground wire that goes to the ground stud on bottom plate contact #68 is a common wire the is connected to the transmission solenoid, the detent solenoid and the work tool pilot solenoid sounds like you have access to the trouble shooting guide have you followed the steps in that publication Mark
be sure to check the detent solenoid on the rt joy stick
Ok I couldn't really trace the wiring as it was a little dirty so I disconnected the battery and washed it all down. I still get OL when I probe #3 and #68. When I probe #3 and then probe something metal like a bolt I get 1.5-3.5 ohms so I'm figuring the ground is good. So I put the connector back on the ecm just to see if it's still flashing and now when you turn the key on the parking light lights up and goes right off. it doesn't flash or stay on like it should. I sure hope I didn't cause damage to the ecm from washing it.
hi, OL is the correct response when you probe #3 and #68 its just saying that the wire #68 is not grounded 1.5-3.5 is also the correct response for wire#3 to ground because it is the ground wire if you have water in connectors unplug and blow out use a hair dryer if you have to or allow time
so if ol is the correct reading to get then what do you think is wrong.. a solenoid? the aux hydralics work, there just is no parking light on now at all when it used to flash as well as the arm rest bar flashed. now i get nothing
have you followed the troubleshooting guide? you have followed the first step there are a number of other steps that check different parts of the circuit
No I stopped following the troubleshooting guide because I kept getting ol so I thought I had a open in the wire. but if I'm supposed to get OL then I will continue to follow that guide. I'm just pretty confused now because I get no flashing lights or solid lights at all now after washing it
Ok so I began to follow the troubleshooting guide and I'm on Step 6, Check the circuit for the hydrostatic pilot solenoid for a short to the + battery terminal. Measure the resistance at the wire harness connector from pin 29 to the following pins, 1, 11, 13, 24, 42, 47, 58, 60, 62, and 70. resistance should be greater than 5k ohms. I believe this is the problem the only pin I have that is getting resistance is pin 24. and about 2 ohms. I am looking for chaffing wires and I do not see anything. Hopefully one of you guys know better than I do.
well done, good find a couple of options from here 1/replace the loom expensive and time consuming 2/spend some time and look /feel for the damaged harness area 3/bypass wire #29 and run a separate wire from the ECM to the left hand joystick xmsn solenoid preferred option would be option #1 but if it was mine I would spend some time on option #2 or #3
Thank you for all the help. I will try option 2 right now but worse comes worse I will do option 3 as I desperately need it for tomorrow. Where does wire #29 go to? I'm trying to look at the schematic but I only have a few years experience so some guidance would be greatly appreciated.
wire #H416 green goes from pin #29 on the ECM to the left hand joystick .the solenoid has a two pin connector .pin # 1 is the other end of H416 Mark
Ok thanks I'm looking now but of course the wires are loomed in something impossible to look through rather then just wire loom. So It's just a straight wire from pin 29 right up to the solenoid? it doesn't go through the fuse box or anything? Thanks
I just probed pin 29 and the green wire on the left joystick solenoid connector and got 000.0 which means that the green wire is good.
Thats right step six is checking that contact 29 wire #H416 green is not touching any other wire. in your post #15 you checked and found that contact 24 wire#p988 was connected some how to connector 29 wire #H416. that does not mean that the wire is broken just shorted to the other wire. by bypassing that area you eliminate the short
Oh ok thanks for the clarification. I will try to find it soon. by any chance do you know where wire 24 goes? Thanks
Ok I'm pretty confused now. I ran a jumper from pin 29 green to the left joystick solenoid and I still get 1.5 ohms going through pin 24. I'm beggining to think pin 29 green to the connector is a good wire. it seems to be either a stuck open solenoid or the white wire off of the solenoid is somehow chaffed with pin 24. What do you guys think? picture attached is the white wire I'm talking about
EDIT IGNORE THE SECOND PICTURE
I unplugged the connector and checked for continuity from the white wire to pin 24 and get 000.0 it's getting power. is that supposed to be a straight wire?
Ok so I already ruled out that the H416-GN wire is good. I'm now onto 975-A46 WH the other wire on the left joystick solenoid is somehow chaffed with P988-A5 OR. I followed where the 988 orange from pin 24 goes and found its in the right joy stick connector I believe conn 27 for the solenoids so I unplugged the connector on the right joystick stick for the solenoids and now I don't get continuity between pin 29 and 24 which is good but then right when I plug it back in I get 2ohms like before I took out the small harness and cut it open and every wire is good in it. I'm running out of things to check
Right below connector 33 on the schematic is where it goes together. P988-R12 OR into the coil on 975-R14 WH. Could that solenoid be bad?
ok I think I know what has happened. as you follow each troubleshooting step you have reconnected the plugs, they should be left unplugged until the process is complete. by leaving the plugs connected to the coils when you measure the resistance between contact 29 and 24 you are measuring the combined coil resistance of the left and right joystick coils as they are connected together via the common return wire 975. my fault I assumed you left the coils unplugged when you tested the circuit you will have to do the procedure again .I realize the procedure in the troubleshooting is vague and I should of realized what was happening Mark
Oh ok thanks I learned a lot though so far so maybe that was for the better haha. I will redo the troubleshooting guide and leave them unplugged as I go and let you know asap. I really cannot afford anymore down time with this thing so hopefully I will find it soon... also do I unplug the battery for this or leave it hooked up? thanks again
Ok I just did the troubleshooting guide. this time I left the ones unplugged as I went through the steps. I'm on Step 8m Check the circuit of the work tool pilot solenoid for a short to battery +. measure from pin 68 to the following pins, 1, 11, 13, 42, 47, 58, 60, 62, and 70. Pin 68 to pin 13 is getting 8.5 ohms.
there is a typo in the trouble shooting guide. it quotes contact 66 wire #975 white it should read contact 68 wire #975 using contact #66 will give you about 10 ohms which is the resistance of the park brake solenoid
Ok so do I proceed with the troubleshooting guide even though I get resistance when I probe pin 68 and pin 13 when I'm not supposed to?
there should be no connection between contact 13 and contact 68
I'm getting connection though when I probe pin 68 and pin 13 so it has to be chaffed somewhere
Ok ignore. I didn't get continuity between 13 and 68. I did the whole troubleshooting guide and everything is ok with the system, does that lead to that the ecu is bad?
Found the problem. I pulled apart the ecu and it was wet. the seal on it went bad so I dried it with a air compressor and then put a heat gun lightly on it. Everything functions well now. Do you think this will fix it for a while as long as it's dry or is it a temporary fix and I should I get a new one at cat for 600$?
I guess the question here is how did the water get into the ECM and can you prevent it happening again..? IMHO if you can (or already have) figure out how the water got in and can take steps to make sure it doesn't happen again then there is really no reason to buy a new ECM.
The drain holes plugged up with mud under the floor board where the ecu was so I had to vacuum out all the mud. It wasn't up very high but it was up a little higher than the base of the ecu so somehow the seal went bad on it so I split the case and saw water in it. I dried it with a compressor and then lightly put a heat gun on it then resealed it with rtv. It works great now so I'm just going to use it as is until I have to replace something else in the future and will clean it throughly after each use now. I recently just got this machine so I didn't know much about how important it is to keep the drain plugs unclogged. Thanks for all the help I have been getting too