Cylinder 12 Contribution/Balance Fault
The P0296 code means the vehicle's onboard diagnostic system has detected: Cylinder 12 Contribution/Balance Fault. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $800 (parts and labor)
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Common Symptoms
- Engine misfire on cylinder 12
- Rough idle and vibration
- Check Engine Light illuminated
- Uneven power delivery
- Engine shakes especially at idle
Probable Causes (Ranked by Likelihood)
- Faulty cylinder 12 fuel injector (incorrect fuel delivery) Very High
- Low compression in cylinder 12 High
- Leaking or clogged injector on cylinder 12 High
- Vacuum leak at cylinder 12 intake runner Moderate
- Worn camshaft lobe affecting cylinder 12 valves Low
Frequently Asked Questions
Can I drive with code P0272?
You can drive short distances with light loads. Cylinder 12 is producing less power than normal, and the engine will run rough. Avoid towing until repaired.
Is P0272 always a serious problem?
Not always. It could be as simple as a clogged injector that needs cleaning. However, low compression or a worn camshaft lobe would indicate a more serious mechanical issue requiring significant repair.
Can fuel quality cause a contribution fault?
Contaminated or low-quality fuel can cause injector clogging and uneven fuel delivery, which may trigger contribution codes. Using quality fuel and periodic injector cleaning can help prevent this.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Perform a cylinder contribution test using a scan tool to compare each cylinder's output
-
Run a compression test -- cylinder 12 should be within 10% of the highest cylinder
-
Swap cylinder 12 injector with another cylinder to determine if the injector is the cause
-
Check for vacuum leaks at cylinder 12 intake port using a smoke machine
-
If compression is low, perform a leak-down test to identify the failure point
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2010-2020 Bentley Continental GT (6.0T W12)
- 2012-2019 Mercedes-AMG S65 (6.0T V12)
- 2008-2018 Aston Martin DBS (5.9L V12)
- 2011-2020 Lamborghini Aventador (6.5L V12)
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