Powertrain, generic · Hybrid propulsion

P0A1C Drive Motor B Control Module Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0A1C is the counterpart of P0A1B for the second electric machine, drive motor B, and reports that its control processor is no longer trustworthy. GM hybrid tables use it for the motor control processor B: in 2016 calibrations the code sets when an inhibit path test at power-down fails three or more times, in 2011 calibrations internal processor integrity faults such as SPI, RAM or cache errors are counted. Both are Type A with MIL on the first trip. The code concerns the control electronics, not a phase current sensor; those faults use their own codes. Expect a hybrid warning and loss of the affected motor function.

Likely causes

Internal processor or memory fault on the motor B control board
Calibration or software fault in the inverter
Unstable 12 V supply or ground to the inverter electronics

Symptoms

  • Hybrid warning and MIL
  • Reduced drive power or no electric drive

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–5,000
Time0.5–8 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

drive motor b control moduleinverter

Related codes

P0A1BP0A79P0A1DP0A1A

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.