Powertrain, generic · Hybrid propulsion

P0AB9 Hybrid/EV System Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Despite the broad title, GM uses P0AB9 for one concrete check: a failed engine auto-start or auto-stop in its hybrids, including an engine stall during that process. In the 2016 and 2019 hybrid tables the hybrid controller sets the code when the engine still reports no torque about 15 seconds into an auto-start although more than 20 Nm is commanded, provided fuel level is sufficient and no cam or crank fault is present. The 2011 and 2013 tables describe the same idea with a stall during start/stop. GM rates it Type A, so the MIL comes on after one trip. Other faults that prevent starting, such as P0A0F, point at more specific causes; P0AB9 itself is the symptom.

Likely causes

Fuel delivery problem (weak pump, nearly empty tank, clogged filter)
Ignition or injector fault that prevents the engine from firing
Starter-generator or motor unable to spin the engine to start speed
Controller software needing an update

Symptoms

  • Check engine light on
  • Engine hesitates, fails or stalls when restarting at a stop
  • Auto-stop disabled for the rest of the trip

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time1–5 h

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

Parts involved

hybrid control moduleenginedrive motor a

Related codes

P0A0FP0AC4

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.