P0291 – OBD-II DTC

OBD-II DTC P0291 – Cylinder 10 Contribution/Balance Fault

DTC P0291 meaning

DTC P0291 refers to a Cylinder 10 Contribution/Balance Fault. This diagnostic trouble code indicates that the Engine Control Module (ECM) has detected an imbalance in the performance of cylinder 10 compared to the other cylinders in the engine. This imbalance can be due to various factors affecting the cylinder’s ability to contribute to the engine’s overall power output.

DTC P0291 symptoms

Common symptoms associated with DTC P0291 may include:

• Rough idling or misfiring of the engine
• Decreased engine performance or power loss
• Increased fuel consumption
• Check Engine Light (CEL) illuminated
• Unusual engine noises, such as knocking or pinging

DTC P0291 causes

Several potential causes for DTC P0291 include:

• Faulty fuel injector for cylinder 10
• Worn or damaged piston rings
• Leaking head gasket
• Faulty ignition coil or spark plug for cylinder 10
• Vacuum leaks affecting cylinder performance
• ECM software issues or faults

DTC P0291 seriousness

DTC P0291 can be serious as it indicates that one of the engine’s cylinders is not functioning properly. If left unaddressed, this issue can lead to:

• Increased emissions
• Further engine damage
• Reduced fuel efficiency
• Potential failure of the catalytic converter

It is advisable to diagnose and repair the issue promptly to avoid more extensive damage and costly repairs.

How to diagnose DTC P0291

To diagnose DTC P0291, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC P0291.
2. Inspect the engine for any visible signs of damage or wear.
3. Check the ignition system components, including spark plugs and ignition coils.
4. Test the fuel injector for cylinder 10 for proper operation.
5. Perform a compression test on cylinder 10 to check for mechanical issues.
6. Inspect for vacuum leaks around the intake manifold and related components.
7. Review the ECM data for any additional trouble codes or abnormalities.

How to fix DTC P0291 step-by-step instructions

To fix DTC P0291, follow these step-by-step instructions:

1. Clear the DTC using an OBD-II scanner.
2. Perform a visual inspection of the engine components related to cylinder 10.
3. Replace any faulty ignition components, such as spark plugs or ignition coils.
4. Test and replace the fuel injector for cylinder 10 if necessary.
5. Repair any vacuum leaks found during the diagnosis.
6. Replace the head gasket if a leak is detected.
7. Recheck the engine’s compression and ensure it is within specifications.
8. Reconnect all components and clear the DTC again.
9. Take the vehicle for a test drive to ensure the issue is resolved.

How to erase DTC P0291

To erase DTC P0291, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the engine to verify that the code does not return.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.