P2AF9Starter Relay D 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
- P2AF9 indicates that the control line of starter relay D sits at supply voltage although the driver is switched off, mostly a short to a 12 V circuit or a leaking driver stage. With ground-side switching the module can then no longer energise the coil, because both coil ends see battery voltage; with supply-side switching the coil may stay energised and keep a cranking path live, which is the more critical case for starter and ring gear. No manufacturer documents P2AF9 publicly. CARB asks for output components to be tested for shorts as well as opens, and GM, as an analogue, treats a path of at most 0.5 Ω toward supply on its starter relay outputs as a short when the driver is off (Type B, 40 of 50). Check the wire for chafing against live circuits, then relay and module output.
- What you may notice
- Stop-start disabled
- Starter may not engage, or in rare cases keep running
- Stored code, lamp depending on manufacturer
- Likely causes
- LikelyControl wire chafed against a live circuit
- PossibleLeaking output driver in the control module
- RareInternal fault in relay D
- 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.