What it means
Cylinder-to-cylinder pressure variation on cylinder 11 is above the calibrated maximum — combustion is unstable cycle-to-cycle, typical of partial misfire or injector seat erosion.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The control module compares pressure behavior across combustion cycles to check whether cylinder 11 is burning consistently. This code sets when pressure variation attributed to cylinder 11 exceeds the calibrated limit, indicating unstable combustion such as a partial misfire or inconsistent injector delivery.
Common causes
Most likely first.
- Unstable combustion in cylinder 11
- Cylinder 11 injector delivery fault
- Intermittent misfire
Symptoms
- Check-engine light
- Rough running or misfire
- Engine vibration
- Reduced engine power
How to diagnose it
- Save freeze-frame data and review cylinder 11 misfire counts and pressure variation to see when the instability occurs.
- Inspect the cylinder 11 injector connector, fuel-related wiring, and pressure-sensor connections for looseness or damage.
- Compare cylinder 11's live pressure pattern and misfire behavior with other cylinders at idle and under the conditions recorded in freeze-frame data.
- Test cylinder 11 injector operation for inconsistent delivery using the manufacturer's procedure.
- If injector and wiring checks pass, investigate cylinder 11 compression and valve sealing to find a mechanical cause of cycle-to-cycle variation.
Common fixes
- Secure or repair a loose cylinder 11 injector or sensor connection.
- Repair damaged wiring causing intermittent cylinder 11 injector or pressure-sensor operation.
- Correct a confirmed cylinder 11 injector delivery fault.
- Repair cylinder 11 compression or valve-sealing problems found during testing.
Can I keep driving?
Avoid hard acceleration if the engine vibrates or misfires. Continued unstable combustion can worsen the misfire and emissions; stop if the rough running becomes severe.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.