P0C4FDrive Motor B Position Exceeded Learning Limit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0C4F covers the second traction motor: its resolver offset learn finished, but the angle it produced lies outside what the controller will accept. GM applies the same two tests as for motor A, an absolute correction above 30 degrees or a change of over 10 degrees against the value kept from earlier learns, both checked at key-off with the rotor nearly still and more than 192 V available. The 2011 Volt sets it on one trip as Type A; the 2016 and 2019 Volt tables also say Type A but wait for five key-off cycles with the angle out of range. No bulletin for this code has been published. A large offset jump usually means something mechanical changed, so the check after a motor or sensor job matters most. P0C18 means motor B was never learned.
- What you may notice
- Malfunction indicator lamp after shutdown cycles
- Reduced propulsion or motor B unavailable
- Unusual noise or shudder under electric drive
- Likely causes
- LikelyMotor B resolver stator fitted in a different position after a repair
- PossibleLearn disturbed by a moving rotor or unstable high voltage at key-off
- RareDamaged motor B resolver giving a shifted angle
- 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 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.