P2AF4Starter Relay C Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2AF4 points to a control wire of starter relay C that carries battery voltage when the module has switched its driver off, typically because it touches a 12 V feed or because the driver leaks. With supply-side switching that can keep the coil energised; with ground-side switching the module can no longer pull the relay in. No manufacturer publishes P2AF4. Relay C is known as Starter Relay 3 at Stellantis, the relay that isolates the auxiliary battery during stop-start restarts, but its published cases concern the stuck codes P2AF5 and P2AF6 only. As a reference, GM checks the tandem starter pinion relay (P26E6) with the driver off for a short toward supply, at 0.5 Ω or less to supply, 40 failures in 50 samples, Type B over two trips. Ground and open faults are P2AF3 and P2AF2.
- What you may notice
- Stop-start disabled
- Relay may stay engaged with ignition off
- Warning lamp depending on manufacturer
- Likely causes
- LikelyControl wire shorted to a 12 V circuit
- PossibleLeaking or failed output driver
- RareWater in the relay socket or power distribution box
- 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.