DTC U1255 Buick
High Voltage Contactor Bypass Contactor Stays Activated (HYBRID MODELS)
High Voltage Contactor Bypass Contactor Stays Activated (HYBRID MODELS)
Description
When the ignition switch is turned OFF and MCM power-supply voltage is a minimum of 10.5 V, IMA motor speed 300 rpm, MPI module voltage is between 90-240 V. The difference of the MPI module voltage before the high voltage contactor opening process and the MPI voltage after the high voltage contactor opening process is 3 V or less after at least 10 seconds. WARNING: The IMA system uses high voltage (144 V), before servicing turn OFF the battery module switch.
Cause and Solution
Poor connections or loose terminals at the high voltage contactor, the bypass contactor, and the MCM Faulty high voltage contactor Faulty bypass contactor Faulty MPI module MCM may need to be updated with the latest software Faulty MCM
Video Guide
Diagnostic Info
- DTC Code: U1255
- Brand: Buick