s/ cat0239dlbl900441 pulling my hair out on this one. Replaced the sensor like a dingus only to find out it wasnt the sensor. found trouble shooting on here. yellow wire and white wire at connector for speed sensor where i only only had 4 volts, wound up finding a break in the pin going to one of the large cannon plugs, Fixed wire now have 8 volts to sensor harness. but im still throwing the same errors. any ideas? any help is much appreciated, long time lurker first time poster
After fixing the problem you need to move the machine quite a distance to generate a new genuine sensor signal before the 2685-8 Diagnostic Code will cease to be Active. Did you do that.?
Did you check continuity on the other two wires from the sensor back to the ECM connector?
Nige, i drove it around the yard for about 10 mins. no change. ahart check continuity with white wire and purple back to ecm? the display on machine is reading 16704.0 rpm for that side drive motor
Did you go all the way through the attached troubleshooting procedure.? BTW your E695-3 Event is a result of the 2685-8. Clear the latter and the former will also disappear.
im now finding i have a break further up the yellow wire. from cannon plug to ecm
any chance someone has an electrical schematic?
I’ll send you one. Keep an eye on your messages.
thank you
equipodezorro,any chance you are in the airplane business? you used the word cannon plug,i know in the airplane world if its a connector we call them cannon plugs.
Been in the rental buisness since high school
update: I had to throw in the towel due to the owner not wanting to waste time chasing a problem i was not familiar with, so we sent the machine up to our local caterpillar dealer. They quoted us to replace lower wiring harness of machine. we went ahead with repair. We were then informed that, they had found active fault codes for the sensors them selves so they replaced both left and right speed sensors. but still could not calibrate drive motors...they apparently ran a test and found internal leakage in both drive motors. They quoted us another repair to the tune of $19500 to replace both drive motors and hydraulic pump. I declined the repair under the assumption the original problem was not corrected. We picked up machine from the dealer and low and behold i still have 4.1v to that sensor. I'm hoping you could shed some guidance on what i should do from here.. i feel the dealer is blowing smoke up my ass?
I bet the owner regrets that decision. A bit of troubleshooting here with members of this forum could have saved a LOT of money. This is very common when taking equipment to the dealer. I have often thought that dealer service has precedents that require everything they repair to cost a minimum of $15K regardless of the problem.
Going from memory and past experience here…..I could be mixed up a bit lol There is a wire in the speed sensor system that is shared with a boom sensor somewhere in the harness. It exhibits some weird symptoms. I’ve also had the short jumper harness from the belly to the speed sensor itself get damaged and throw codes. I don’t personally see how electrical issues can be attributed to internal leakage in the hydraulic system. That would be easy to verify through running a case drain test of your own. It’s rare but the machine ECM’s do go bad. How many hours on the machine? Are you aware of any other issues? Signs it’s been welded on or anything that could explain some haywire electrical symptoms?
i got a better look at machine today, both speed sensors dont voltage when plugged in. when disconnected both are at little over 4v. I also do not have the speed sensor codes saved in display. new codes are as follows 1703-13 1704-13 1705-13 1706-13
junkyard to answer your question, this machine has no boom sensor. i dont believe anyone has welded on the machine
-13 means calibration required. 1703, 1704, 1705, 1706 refers to all 4 solenoids on your main hydrostatic pump. These are most likely active because the dealer attempted a calibration and the calibration failed. It failed likely because a) worn components in the hydrostatic system were not responding correctly (the pumps/motors they quoted you to replace), or b) an electrical fault occured during the calibration (such as a speed sensor fault) and the calibration aborted. Only way to clear these now is to run a successful pump/motor calibration. Find out for yourself. a) Cut hydraulic filter open, check for debris. These sensors run in hydraulic oil. If that oil is contaminated with metalic stuff the sensors can't do their job properly. b) Check flow out of the case drains on the pumps and motors at high idle, full command in any direction. It's painful because you need to lower the cab to sit in it. Raise machine off the ground. You can set up some hoses running out of the belly plate or you can set up a phone camera or gopro with a torch. Sometimes you can remove some panels off the side of the cab to eyeball the case drain ports. Either way you need to identify which motor(s) or pump(s) have high case drain flow. Sometimes it's easier to just quote all new pumps/motors which looks exactly what the dealer has done in this case. Machine hours also play a factor in this. You never stated, did you run through the entire troubleshooting procedure Nige sent you?
found my voltage drop for sensor wires. next step on troubleshooting was disconnecting main connectors from ecm jumped my purple and yellow signal wires at switch and had no continuity. purple tested fine from sensor up. saw they ran a new yellow wire from ecm to large round deutcsh plug went to move wire to push in my back probe spoon in wire came out and pin stayed in. super!
It would appear not.............