J1939 Termination Resistance Drift: The 4.7 Ohm Hot vs Cold Difference That Kills Communication
A 2021 Kenworth T680 rolled into a Midwest fleet shop with a CAN bus fault that had already burned five days of diagnostic time. The truck had a PACCAR MX-13, 187,000 miles on the odometer, and a cab-side termination assembly that still looked factory-fresh. The shop had swapped the ECU, the instrument cluster, and the […]