P2DC7Starter/Generator Excitation Current
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2DC7 is the general fault for the excitation current of a starter/generator, meaning the DC current in the rotor field winding does not behave as commanded. Only wound-field machines have one. Valeo's 48 V belt starter generator, for instance, is a synchronous claw-pole machine; in such designs the stator gets three-phase current from an inverter, while a separate H-bridge drives direct current through brushes and slip rings into the rotor coil. Permanent-magnet starter/generators need no excitation, so the code does not apply to them. Regulator chips for wound-field alternators measure this current and can limit it, which is the basis for such checks. Switching the field off is also a safety tool against DC-link overvoltage. No manufacturer documents P2DC7 publicly. Low: P2DC8; high: P2DC9.
- What you may notice
- Battery or charging warning lamp
- Starter/generator stops charging and assisting
- Stop-start disabled
- Likely causes
- LikelyWorn brushes or contaminated slip rings on the rotor
- PossibleFault in the excitation H-bridge of the starter/generator electronics
- PossibleRotor field winding with interrupted turns or a short
- 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: €150 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.