P0C0BDrive Motor A Inverter Power Supply Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0C0B flags a lost or interrupted supply inside the motor A inverter. GM reads it from the IGBT module status: when the gate drive supply falls below its threshold, the module reports a bias fault; on eAssist the 5 V rail below 3.5 to 4.3 V or the 15 V rail below 10.4 to 12.6 V counts, with run/crank above 7 V. The 2012 trucks enable it between 9.5 and 18 V; the 2016 to 2019 tables need 0.002 to 0.168 s of fault within short windows, Type A, one trip. Mercedes applies the code to the high-voltage supply of the inverter in the belt starter-alternator of P3 hybrids (subtypes 16 and 17) and replaces that unit. Expect loss of electric drive or engine start.
- What you may notice
- Malfunction indicator lamp after one drive
- Electric drive or motor generator unavailable
- Engine cannot be started, only electric driving possible (Mercedes P3 hybrids)
- Likely causes
- LikelyFailed gate-drive power supply inside the motor A inverter
- PossibleLow 12 V feed, blown fuse or poor ground to the inverter control board
- RareOpen high-voltage feed to the inverter, e.g. in a belt starter-alternator (Mercedes LI15.40-P-077947)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.