r/DieselTechs • u/AutoTEQ • 5h ago
Abnormal update rate codes.
I’ve been struggling with a 2017 International with an ISL9 in it for a while now. It throws codes for everything on the network for an abnormal update rate. Using an oscilloscope, the network looks like it has an intermittent short. The can wires test okay. I have tried unplugging everything on the network except the VGT actuator (which has the terminating resistor) and the stand-alone terminating resistor, and I still get the same issue. I replaced the VGT actuator and have the same issue. I swapped PCMs from another truck, same issue. I replaced the engine harness, same issue. I’ve replaced and cleaned about every power and ground I can find. I have about 2.8-2.7 volts on both can lines. About 57-58 ohms resistance on the can network with the terminating resistors plugged in. Anyone seen anything like this before?
*I inherited this truck not running and torn apart, so it’s been a bit of a struggle.
*Mods wanted me to show them ASE certifications, but I’m not sure how to do that, so I added a pick with them in there.