Volt

DTC P0AB9

This vehicle does not use a 12 V starter motor to crank the internal combustion engine. A much more powerful 300 V drive motor 1 located within the transmission is utilised to crank the engine. The 300 V drive motor 1 can rotate the engine to operating speed (800 RPM) within just a few hundred milliseconds. The hybrid powertrain control module can detect a condition where the engine is cranking but does not start or has stalled.

Drive motor 1 is cranking the engine.

The hybrid powertrain control module detects that crankshaft position sensor engine speed has not risen above the commanded cranking speed, indicating the engine has failed to start, or the hybrid powertrain control module detects crankshaft position sensor engine speed has fallen below a specific minimum speed indicating the engine has stalled.

DTC P0AB9 is a Type A DTC.

Cranks But Does Not Start

When the system orders engine Crank, the hybrid powertrain control module will command drive motor generator 1 to rotate the engine. The drive motor will continue to rotate the engine at a specific RPM until the engine starts and causes increased engine RPM. The hybrid powertrain control module will cease engine rotation if an increase in engine RPM is not observed after several seconds. This function may have the appearance of a start/stall condition.

Engine Stall

If stalling occurs after a successful engine start, the hybrid powertrain control module will recognize the drop in engine RPM and command drive motor generator 1 to maintain engine RPM in an attempt to restart the engine. Drive motor generator 1 will continue to rotate the engine until the hybrid powertrain control module commands it to stop. The engine may be rotated for many minutes after the actual engine stall condition occurred and is typically stopped only after the hybrid battery state of charge gets too low. This function may have the appearance of a running engine.

DTC P0AB9 is a Type A DTC.

Any condition that causes the engine to stall and/or not start may set this DTC. Possible conditions include:

Always inspect for DTCs that would cause an engine stall and/or no start condition.

This DTC may set if the vehicle is powered off while driving.

1. Vehicle ON. Operate the hood release to open the hood. The engine should start and run.

⇒	If the engine fails to start, diagnose the engine system. Refer to Engine Cranks But Does Not Run .

2. If the engine starts, the problem is intermittent and not present at this time.
3. DTC is set, and the engine is running, program the T6 power inverter module.

⇒	If the DTC resets, replace the T6 power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module, also called the power inverter module, replacement, programming and set-up.