Customer has a 4045HF285 engine that has a bad ECM. Problem is that on the ECM, CAN LO is 5 ohms to ground, therefore it can't communicate to the rest of the unit and the controller shuts it down for lack of comm. It runs fine and everything, so I suspect it could be fixed by fixing whatever is wrong with the CAN line, but I don't know if there is anybody we can recommend to do it.
It’s been my experience that anything computer related to Deere has to be done by the dealer.
I sent one to a shop in S C . Pure scam, never was opened.
So the CAN issue is definitely on the ECM side, not the wiring side? You're most likely looking at a dealer fix than an aftermarket repair. Previously had a local Deere tech that saved a Powertech ECU with a bad temp sensor reading so he could swap it and easily see if any other fault was real or ECU related. Keep hoping to stumble onto one of those...
When the harness is disconnected from the ECM there is 60 ohms CAN H to CAN L and several kohms H and L to CAN shield. When I connect the harness it to the Deere ECM, CAN L has 5 ohms to CAN shield. So the ECM has some kind of a near short on the CAN L wire. Voltages when running bear this out, normally CAN H and CAN L will run several volts above ground with H being a bit higher, on this one CAN L is near zero volts as expected with that load pulling it down. I also have a spare genset controller on a Detusch diag connector I use to confirm, it also has no comms to the ECM. I am thinking this should be a simpler repair for a properly equipped shop since it appears to be something like a protector component near shorted to ground but I don't know if any shops are trustworthy.
I have used these people for instrument cluster repairs, but have not used them yet for an ECU. Might be worth a call. Circuit Board Medics I have never used this outfit at all, but might be worth a call as well. Industrial Repair
Its just too bad all these black boxes in machines and automotive never have any sort of service information available. Sounds like an easy fix with the right service info available.
I would try to fix it myself but I am afraid I might break something trying to get in. I bet it is just some kind of circuit protector component mostly shorted to ground. I used to do circuit board repair but this is not the unit to get started on, too valuable to experiment with. Also a specialty shop might know tips and tricks they learned the hard way and I don't know about.
decent video replacing the resistors & rebuilding the board
I did not read all responses there is a great place in Kamloops BC canada Jerry's diesel
Deere 500a: Great video. I will try the exact same repair, in the not too long distance future. Was the calibrating started by pushing the Enter Button (X) number of times. Will watch a few more times. Thanks for the info, great of you to share these gems of Knowledge. Probably the calibration process is spelled out in the service manual. Thanks Again, Will be watching a few more of your videos for info. Simion C
Yes it is.