Cylinder 4 Contribution/Balance Fault
The P0272 code indicates that the engine control module (ECM) has detected a lack of contribution from cylinder 4 during the power balance test. This means cylinder 4 is not producing as much power as the other cylinders, often due to fuel delivery issues, ignition problems, or mechanical faults. The ECM monitors crankshaft acceleration to identify weak cylinders.
01. Most Common Causes
- Faulty fuel injector on cylinder 4
- Ignition system issue (spark plug, coil, or wire)
- Low compression in cylinder 4
- Vacuum leak affecting cylinder 4
- Engine mechanical problem (valve, piston, or ring)
02. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Poor fuel economy
- Engine vibration at idle
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Perform a power balance test to confirm cylinder 4 is weak.
Step 3: Inspect spark plug and ignition coil on cylinder 4; swap with another cylinder to see if misfire follows.
Step 4: Check fuel injector on cylinder 4; listen for clicking or use a noid light.
Step 5: Perform a compression test on cylinder 4 and compare to others.
Step 6: Inspect for vacuum leaks and check engine mechanical condition.
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 it can cause catalytic converter damage and poor performance. Short trips to a repair shop are okay.
How much does it cost to fix?▼
Costs vary: a spark plug replacement is $50-$150, a fuel injector $150-$400, and compression repairs can exceed $1000.