P2C28Fuel Injector Group B Supply Sense Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2C28 is set when the sense line of the injector group B supply shows more voltage than allowed – either above the upper limit while the group is switched on, or voltage present while the module has switched the group off. Common reasons are a welded injector relay, a supply wire chafed against another powered circuit, or a sense wire shorted to battery voltage. A supply that cannot be switched off matters because the module can no longer isolate the group when it needs to protect an injector or the catalyst. No publicly accessible manufacturer document covers P2C28; it follows CARB's demand for separate high-range codes, and GM's handling of injector supply faults on the Saab 9-5 2.0T (wrong voltage for over 1 s, Type B, injector disabled) gives a comparable logic.
- What you may notice
- Check engine light
- Often no noticeable change in running
- Battery drain if the relay stays closed after switch-off
- Likely causes
- LikelyInjector relay contacts stuck closed
- PossibleSense or supply wire shorted to battery voltage
- RareExcessive system voltage from the charging system
- RareInternal fault of the supply switch in the engine control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.