S/N: XKY00260 1235-9 : J1939 Network #3: Abnormal Update Rate Machine is in derate because of this code. I'm following the troubleshooting on Cat Sis article #i10249044. I checked the 2 resistors for this circuit and they had roughly 59 ohms, which is within spec. Next it says "measure the voltage between the Sensor Supply (+) and Sensor Ground (-) terminals on the wiring harness connector of the device that is not communicating." How do I know which device/sensor it is? I will post a picture of what the system communication status page shows.
What is device #2 supposed to be?
I checked sensor supply voltage for the DOC inlet temp sensor. It was at 5V. If that’s device #2, do I need to replace the sensor?
I checked the system communication status again and it showed more info now. I checked voltage to the def tank header unit and had battery voltage.
Seeing the def level at 66.3%, I thought to top it off to see if the level changes. No % change after topping it off, but after I did that and started the machine, the code and derate went away. Def level is still at 66.3% and the tank temp still won’t show. I’m assuming the heater unit is bad?
That's going to take a DEF tank header. I think those have a 60 month 3000 hr emission warranty. Don't clear any codes or events until the dealer can take a PSR or they may have trouble getting coverage. You say you checked for voltage but also check the coolant diverter isn't stuck/leaking as overheated DEF will damage the header when it gasses ammonia off.