OBD-II code · Powertrain (generic)
P05F9 Stop-Start Status Signal Circuit
A general circuit fault on the stop-start status signal - the bus or hardwire that tells other modules whether the engine is auto-stopped or running.
Is it safe to drive with P05F9?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in signal line
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.2 h
- Emissions test
- Usually unaffected
- Parts involved
- Stop Start Status Signal
Related codes
- P05F6Exhaust Aftertreatment Power Relay Control Circuit Stuck On
- P05F7Exhaust Aftertreatment Power Relay Control Circuit Stuck Off
- P05F8Reductant Heater Control Module Performance
- P05FAStop-Start Status Signal Circuit Low
- P05FBStop-Start Status Signal Circuit High
- P05FCCold Start Fuel Pressure Performance Bank 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.