Powertrain, generic · Hybrid propulsion

P0A1B Drive Motor A Control Module Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0A1B flags a self-test failure of the processor that controls drive motor A, usually inside the inverter. In GM hybrid tables (2016) it sets when the processor fails an inhibit path test at power-down, three or more times, proving it could not take the system to a safe state; in 2011 tables internal SPI, RAM or cache faults in 28 of 32 samples count. Both are Type A, MIL on the first trip. Land Rover sets P0A1B in the inverter of 2024-25 PHEVs at start-up, VW lists P0A1B00 for the ID.4 front drive. Toyota uses subtype P0A1B-1F on the 2023-24 Corolla Hybrid. Drive motor B is P0A1C. Expect a red loss-of-drive warning.

Likely causes

Control software fault, several makers resolve it by reprogramming
Internal processor or memory fault in the inverter control board
Weak 12 V supply during start-up or shutdown

Symptoms

  • Loss of drive warning and MIL
  • Vehicle cannot be driven electrically or not at all
  • Fault may vanish after a full sleep cycle while the code stays stored

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 a control module

Related codes

P0A1CP0A1AP0A78P0A90P0A1D

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.