P05F9Stop-Start Status Signal Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- A discrete stop-start status line tells the engine module (or another module) whether stop-start is active, inhibited or has just stopped the engine. On most current cars this status travels over CAN instead, so a hard-wired line and these codes are rare; no manufacturer document available to us uses P05F9–P05FB. CARB names stop-start as its example of an 'emissions neutral' reaction: a module that simply disables stop-start when a fault appears may report it without the check engine light, which is what Ford does for its stop-start codes. P05F9 is the general circuit fault or open line. The typical reaction is that stop-start is disabled; the driver-operated stop-start switch has its own codes.
- What you may notice
- Stop-start does not work
- Stop-start indicator or message in the cluster
- Check engine light only with some makers
- Likely causes
- LikelyOpen status line or connector problem
- PossibleSending module without supply or faulty
- RareWrong software or variant coding (stop-start set without hardware)
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.