Hello, this error says that "the monitor has detected CAN communication error between pump controller and engine controller". I've check all of the CAN-BUS wiring and it's perfectly fine. I can also see messages on CAN-BUS network with my oscilloscope. The machine works normally, but there is no info about the engine temp, fuel level etc. on the monitor. Also, the air condition control doesn't work (also on CAN-BUS system). It seems like the monitor is not reading info from the CAN-BUS system. That could be a faulty monitor but it doesn't correspond the error description. Any thoughts on this?
Hope to be helpful. Good luck.
Result of my troubleshooting: faulty monitor or to be more precise - faulty connector pins soldering on the monitor printed circuit board.
Actually, I was wrong. Although it seems that I gain connection when I press on the connector, changing both the connectors on the board and on the harness didn't solve this issue. I still have no data from the engine, pump and A/C controller coming from the CAN-BUS system. Any toughts?
I might be wrong but, If you took at 1156 Tail light bulb with a pigtail harness and hooked it up to power on one end and ran the other end of the pigtail into the CAB-BUS wires one at a time. You would have to disconnect the CAN-BUS wires at the other end and test each section with the other end going to ground. The 1156 bulb uses 2.1 Amps and would be sufficient load to test those wires. I would run that power through my meter to see if it is grounding out somewhere. It would possibly record more on my recording meter. Maybe this is how you tested it, but if it was just an OHM meter test and there was even the weakest path through it would test okay. Once you add heat and vibration, the thing would fail. I put a long red 16 gauge wire on my pigtail on one side with alligator clips and a black 16 gauge wire on the other end of the pigtail with an alligator clip. Works well for me. Simon C
We changed the CAN-BUS chip on the monitor PCB -> error remains.
So how did you test the Can-Bus harness. Did you flow current through the wires. Just wondering. Simon C
I disconnected all the controllers and check the harness for continuity. Checked the 120 Ohm resistor. Connected all back and measured with an handheld oscilloscope. I can see a lot of traffic on the CAN-BUS and two nice waveforms ranging from 1.5 to 3.5 V. No, I didn't flow current thru the wires. Should I?
Nige has said, and I agree that even the tiniest path through will be a pass for continuity test but can act up. As I posted in #5, a flow of current may identify a weak harness. Maybe test and who knows what will come up. Simon C
Well, I've watched the CAN-BUS with oscilloscope back probes on monitor connector with all the controllers and monitor connected. That's loaded enough, so I guess it's not necessary to load test the harness now. I think the monitor is bad but it's just that I'm never 100% sure. I mean the error is "the monitor has detected CAN communication error between pump controller and engine controller" and on the other side; the monitor doesn't show anything from the CAN-BUS. Even A/C controls don't work and that's also on CAN-BUS. And there is traffic on the CAN-BUS.
You are probably right, but no one likes to get caught with a simple fix afterwards. If you did all you posted , you are probably into some monitor expense. What is it worth other than an arm and leg. Simon C
I'm looking into buying a new monitor. My part number is 7835-31-1012 but the dealer is offering me 7835-31-1017. Also, on websites everybody is offering 7835-31-1004. What's the analogy between these parts?
When you want to buy spare parts for Komatsu machines, you must provide information about the machine's serial number. The reason is that even if the machine model is the same, but the serial number is different, their spare parts may also be different.
Yes LACHAU is correct as there are many changups that are done in their parts world. Without the serial number you could buy for example 1 of 4-5 different oil pans, that will fit on a block but be wrong in some way. The pump piping is different or whatever. For your monitor, best to find out the exact serial number/ part number combination and save a lot of grief. Simon C
To be clearer, as I said. Please see the attached pictures, you will see the part number changes depending on the serial number of the machine.
Yes, I understand that... I took the part number of the monitor itself.
So, I ordered an aftermarket monitor via Alibaba. It arrived in less then ten days. From the outside the quality looked quite good. Only complain is that the screen plastic felt quite soft. Like you could scratch it just by using a dirty rag. The buttons have a different sound but still feel good. On the software side it seems that I end up with something newer. The interface looked fresher then on the old one. Unfortunately, some parts of the monitor and machine functions don't work. Like camera and two-way auxiliary hydraulic functions via potentiometer on the joystick. You can enter the service menu, everything is there, but some sensors wasn't reading any data. Overall, I would say that 95% of the monitor functions are working compared to original monitor. Luckily, my customer didn't need any of the mentioned above and with the price saving he was happy to keep the aftermarket monitor. I would like to mention that the Chinese gentleman tried to help me resolve the issues above but it's was also hard for him to receive any info from the manufacturer.
Glad you got somewhat solved. Did it cost an arm and leg.? Simon C