P0291Cylinder 11 Injector A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0291 means the control wire of the cylinder 11 injector – the side the engine module switches to ground – is shorted to ground. GM detects this with the driver off: on direct injection at 1 V or less, on port injection and Duramax diesels at 0.5 Ω or less to ground. Ford's 6.7 diesel has its driver chip report the short within 0.3 s. Most systems switch the warning light on in the first trip (some GM port-injection engines and Saab's 2.0 turbo after two) and shut the affected injector off, so the cylinder misfires. Ford petrol engines report all injector circuit faults as P0201 ff instead. Cylinder 11 exists only on twelve-cylinder engines; no manufacturer document using this code was found – GM and Ford documents stop at cylinder 8 – so the description follows CARB and the codes for cylinders 1–8.
- What you may notice
- Check engine light on
- Misfire and rough running, misfire code P0311
- Loss of power, rough idle
- Injector shut off, limp mode possible on diesels
- Likely causes
- LikelyControl wire of the cylinder 11 injector chafed to ground in the harness
- PossibleInjector connector damp or corroded, leakage to ground
- PossibleInjector shorted to its housing internally
- RareOpen control wire (on some GM port-injection drivers this also reads low; P020x sets too)
- RareDriver stage in the engine module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.