GMT201 Intermittent No Crank No Start VSS Harness Short To Ground - keywords communication crank ground hot intermittent loss LX9 nocrank nostart

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

A technician may report an intermittent no-crank concern. They may report no communication with the PCM, and/or that the 5 volt PCM output supply is only 3 volts, and/or vehicle speed DTC P0608 set, and/or communication DTC codes set by other vehicle modules.

This concern could be caused by an intermittent short to chassis ground of the Powertrain Control Module VSS output @ J1-22. Please inspect the 389 circuit for short to a chassis ground.

One vehicle example was the harness on circuit 389 which is the VSS output speed signal from PCM to rear parking assist module, radio, and throttle body was intermittently shorted to chassis ground when the vehicle interior was at a high ambient temperature. This concern was more prevalent with high ambient temperatures. Technicians may not correlate the changing temperature to the concern. The technician can run the vehicle with the heat on high for an extended period to duplicate high ambient temperatures.

Please inspect circuit 389 for short to ground.

Repair any damaged insulation/wiring if found, then secure/route harness to prevent further chaffing.

Note: One area to inspect is at the rear of the right hand sliding door floor pan area. (This is the circuit to URPA)

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.