P2A34AFCM Power Relay Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- With P2A34 the coil control line of the gas module power relay stays at high voltage even when the driver tries to pull it to ground. Either the wire has contact with a battery-fed circuit, or the coil draws so much current that the driver shuts itself off for protection. In both cases the relay does not close. The consequence is the opposite of P2A33: the alternative fuel module receives no switched supply, so gas operation is impossible, and a bi-fuel car falls back to petrol from the start. Public documents for P2A34 are lacking; GM Europe treats the engine version P0687 on the 2010 Saab V6 with the same comparison of commanded against measured state. Ford's 2003 bi-fuel CNG design shows that the AFCM is a separate unit with its own power and relay outputs.
- What you may notice
- Check engine light, depending on calibration
- Gas operation unavailable, bi-fuel vehicle runs on petrol only
- Dedicated gas engine: cranks but does not start
- Likely causes
- LikelyControl wire shorted to a battery-fed circuit
- PossibleRelay coil with too low resistance overloading the driver
- RareWrong relay type fitted after a repair
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.