P2D9CStarter/Generator Phase V Current Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2D9C reports an erratic current signal on phase V of the starter/generator. V is the phase that some designs never measure: in a star-connected three-phase winding the three currents add up to zero, so GM's eAssist table runs sensor checks only on U and W. Other inverters fit a sensor to every phase conductor, often a Hall chip in a ring core whose output voltage follows the current. A system that stores P2D9C therefore evaluates phase V on its own, and an unsteady value there leads to the V sensor, its plug or its leads rather than to the other two phases. No manufacturer documents P2D9C publicly. Drivers notice a sporadic warning and short gaps in stop-start or boost. Neighbours: P2D9B (U) and P2D9D (W).
- What you may notice
- Sporadic system warning on the instrument cluster
- Short interruptions of stop-start or boost
- Likely causes
- LikelyPhase V sensor plug not fully latched or with fretting corrosion
- PossibleIntermittent break in the phase V sensor wiring
- RarePhase V current sensor with unstable output
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.