DTC U0100 : Lost Communication with ECM/PCM A: Description

The PSCM monitors the HS-CAN bus when the ignition has been on for more than 5 seconds, when the voltage to the PSCM is greater than 9 volts and when there are no DTCs present that are inhibiting PSCM operation.

DTC U0100:00 (Lost Communication with ECM/PCM A: No Sub Type Information) - This DTC sets if communications between the PSCM and the PCM fail. If the engine speed signal is missing for greater than 1 second(s) this DTC sets.