What it means
The closed-loop combustion controller reports that combustion performance on cylinder 2 is below the calibrated quality metric. Computed from the cylinder pressure trace — IMEP (indicated mean effective pressure), CA50 (50% mass burnt angle) or peak pressure deviates from the model.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The engine control module uses the cylinder 2 pressure trace to assess how effectively that cylinder is producing and timing combustion. This code sets when cylinder 2's calculated combustion performance falls outside the calibrated quality range, which can reflect injector flow drift or a problem with the pressure signal or control data.
Common causes
Most likely first.
- Injector flow rate drift
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Check engine light on
- Rough running or engine misfire
- Reduced power
- Uneven acceleration
How to diagnose it
- Save freeze-frame data and review cylinder 2 pressure and combustion performance readings at the recorded engine speed and load.
- Compare cylinder 2 performance with the other cylinders and check for related injector, sensor, or communication codes.
- Inspect the cylinder 2 pressure sensor and injector connectors and wiring for damage, corrosion, or loose terminals.
- Check cylinder 2 injector operation and fueling data for signs of inconsistent flow.
- If the cylinder-specific hardware checks out, verify the relevant module communication and combustion control data against the manufacturer's service information.
Common fixes
- Repair a damaged cylinder 2 sensor or injector connector and its wiring.
- Correct a confirmed cylinder 2 injector flow problem.
- Replace a faulty cylinder 2 pressure sensor if its signal is outside specification.
- Repair a confirmed communication or engine control fault affecting cylinder 2 combustion data.
Can I keep driving?
Limit hard acceleration if the engine runs roughly or responds unevenly, and have the cause checked soon. Poor cylinder 2 combustion can reduce power and increase emissions; persistent misfire may also damage the catalytic converter.
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.