Cylinder 12 Contribution/Range Fault
The P0296 code indicates that the Engine Control Module (ECM) has detected a lack of contribution from cylinder 12, meaning the cylinder is not producing the expected power. This can be caused by mechanical issues (low compression, faulty valves), fuel delivery problems (injector, fuel pressure), or ignition system faults (spark plug, coil). The ECM monitors crankshaft acceleration to identify weak cylinders.
01. Most Common Causes
- Faulty fuel injector on cylinder 12
- Low compression in cylinder 12 (worn rings, valves, head gasket)
- Ignition system failure (spark plug, ignition coil, or wiring)
- Vacuum leak or intake manifold gasket leak affecting cylinder 12
02. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Increased fuel consumption
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Perform a cylinder power balance test to confirm cylinder 12 is weak.
Step 3: Inspect spark plug and ignition coil on cylinder 12; swap with another cylinder to see if misfire follows.
Step 4: Test fuel injector on cylinder 12 for electrical resistance and spray pattern.
Step 5: Perform a compression test on cylinder 12 and compare to others.
04. Commonly Affected Makes
05. 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 cause further engine damage. Limp home if necessary.
How much does it cost to fix?▼
Costs vary: spark plugs $50-$150, ignition coil $100-$300, fuel injector $150-$600, compression repairs $500-$2000+.