P0291
Cylinder 11 Injector A Circuit Low
Fuel injector circuit
Generic OBD-II
High
What it means
P0291 means the engine controller has detected low voltage (a short to ground or an open) in the fuel injector control circuit for cylinder 11. With the circuit out of spec, that cylinder may not fire correctly, so the engine runs rough and loses power. It's an electrical fault — usually the injector wiring, connector, or the injector itself.
High
Can I keep driving? You can usually drive, but cylinder 11 may misfire and run rough. Prolonged misfiring can damage the catalytic converter, so fix it soon.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or a steady miss from one cylinder
- Reduced power and hesitation
- Possible increase in fuel consumption
Common causes
Most likely first
- Short to ground or open in the cylinder 11 injector wiringLikely
- Failed fuel injector on cylinder 11Common
- Loose or corroded injector connectorCommon
- Failed injector driver in the engine control module (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is on the cylinder 11 injector circuit.
- Inspect the injector connector and wiring for a short to ground, chafing, or corrosion.
- Measure the injector's resistance and compare it to the other injectors.
- Swap or bench-test the injector if suspect; repair wiring faults first.
- If the circuit and injector are good, have the ECM's injector driver checked. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0291?+
For short distances, but a dead or misfiring cylinder 11 can overheat the catalytic converter over time. Get it repaired promptly.
Can I just clear P0291?+
It will return until the injector wiring or the injector itself on cylinder 11 is fixed.
Related codes
Often seen with P0291
Read & clear P0291 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX