P1159 – OBD-II DTC

OBD-II DTC P1159 – Bank 2 Fuel Control Shifted Rich

DTC P1159 meaning

DTC P1159 refers to a diagnostic trouble code indicating that the fuel control system for Bank 2 is operating in a rich condition. This means that the engine is receiving too much fuel relative to the amount of air, which can lead to inefficient combustion and increased emissions. The “Bank 2” designation typically refers to the side of the engine that does not contain cylinder 1, which is important in V-type engines.

DTC P1159 symptoms

Common symptoms associated with DTC P1159 may include:

• Decreased fuel efficiency
• Rough idling or engine misfires
• Increased exhaust emissions
• Check Engine Light illuminated
• Loss of power during acceleration

DTC P1159 causes

Several factors can contribute to the occurrence of DTC P1159, including:

• Faulty fuel injectors
• Defective oxygen sensors
• Vacuum leaks in the intake system
• Malfunctioning mass air flow (MAF) sensor
• Fuel pressure regulator issues
• Excessive fuel pressure

DTC P1159 seriousness

DTC P1159 is considered a moderate to serious issue. If left unaddressed, it can lead to:

• Increased fuel consumption
• Potential engine damage due to improper combustion
• Failing emissions tests
• Long-term damage to the catalytic converter

How to diagnose DTC P1159

To diagnose DTC P1159, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1159 code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the fuel system for leaks or damage.
4. Test the fuel pressure to ensure it is within specifications.
5. Examine the oxygen sensors and MAF sensor for proper operation.
6. Check for vacuum leaks in the intake system.
7. Perform a visual inspection of the wiring and connectors related to the fuel control system.

How to fix DTC P1159 step-by-step instructions

To fix DTC P1159, follow these step-by-step instructions:

1. Address any vacuum leaks found during diagnosis.
2. Replace faulty fuel injectors if they are not functioning correctly.
3. Replace or repair defective oxygen sensors.
4. Clean or replace the MAF sensor if it is malfunctioning.
5. Adjust or replace the fuel pressure regulator if fuel pressure is excessive.
6. Clear the DTC using an OBD-II scanner.
7. Test drive the vehicle to ensure the issue is resolved and the code does not return.

How to erase DTC P1159

To erase DTC P1159, 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 Codes” 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.