Cylinder 5 Contribution/Balance Fault
The P0275 code indicates that the engine control module (ECM) has detected a misfire or imbalance in cylinder 5's contribution to engine power. This is typically caused by a faulty fuel injector, but can also result from issues with the ignition system, low compression, or wiring problems. The ECM monitors crankshaft speed variations to identify cylinders that are not contributing equally, and when cylinder 5 deviates beyond a threshold, this code is set.
1. Most Common Causes
- Faulty fuel injector on cylinder 5 (electrical issue or clogged)
- Low compression in cylinder 5 (worn rings, leaking valves, blown head gasket)
- Misfire on cylinder 5 (bad spark plug, ignition coil, or wiring)
- Vacuum leak specific to cylinder 5 (intake manifold gasket, head gasket)
- Internal engine mechanical problem (camshaft, lifters, pushrods)
- Erratic crankshaft or camshaft position sensor signal
- Faulty PCM (unlikely)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced power and fuel economy
- Possible hesitation or stumbling during acceleration
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Perform a cylinder contribution test using a scan tool to confirm cylinder 5 is weak.
Step 3: Swap the fuel injector from cylinder 5 to another cylinder and see if the misfire moves.
Step 4: Check spark plug, ignition coil, and wiring for cylinder 5.
Step 5: Perform a compression test on cylinder 5.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the misfire can damage the catalytic converter and reduce fuel economy. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost varies depending on the cause. A fuel injector replacement typically costs $150-$400 including parts and labor. Ignition components are usually cheaper.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.