System Too Rich at Higher Load Bank 2
Bank 2 fuel system is running too rich (excessive fuel, insufficient air) under higher engine loads. The oxygen sensor or air/fuel ratio sensor detected a fuel mixture that is significantly richer than the target ratio, indicating either a fuel delivery problem or an intake air measurement issue.
What You Might Notice
- Check engine light illuminated
- Reduced engine power or acceleration hesitation
- Occasional misfires during acceleration
- Poor fuel economy
- Black smoke or sooty exhaust
Most Common Causes
- 1
Faulty oxygen or air/fuel ratio sensor
A failed or degraded O2/AFR sensor on Bank 2 may send incorrect signals to the PCM, causing it to add too much fuel. This is the most common cause of this code.
- 2
Faulty mass airflow sensor
A contaminated or failing MAF sensor provides inaccurate air mass readings, causing the engine computer to miscalculate fuel demand and add excess fuel.
- 3
Fuel injector stuck or leaking
A stuck-open or continuously leaking fuel injector on Bank 2 cylinders will introduce more fuel than needed, creating an overly rich condition.
- 4
Faulty powertrain control module
In rare cases, a defective PCM may incorrectly calculate fuel trim values and command excessive fuel delivery despite proper sensor inputs.
How to Diagnose It
- 1
Check Faulty oxygen or air/fuel ratio sensor — A failed or degraded O2/AFR sensor on Bank 2 may send incorrect signals to the PCM, causing it to add too much fuel. This is the most common cause of this code.
- 2
Check Faulty mass airflow sensor — A contaminated or failing MAF sensor provides inaccurate air mass readings, causing the engine computer to miscalculate fuel demand and add excess fuel.
- 3
Check Fuel injector stuck or leaking — A stuck-open or continuously leaking fuel injector on Bank 2 cylinders will introduce more fuel than needed, creating an overly rich condition.
- 4
Check Faulty powertrain control module — In rare cases, a defective PCM may incorrectly calculate fuel trim values and command excessive fuel delivery despite proper sensor inputs.
How to Fix It
- 1
Replace Bank 2 oxygen or AFR sensor
Locate and replace the oxygen sensor (or air/fuel ratio sensor) on Bank 2. Start with this most common fix; remove the old sensor from the exhaust manifold or pipes and install a new sensor, ensuring proper torque and clearance.
- 2
Clean or replace mass airflow sensor
Inspect the MAF sensor for contamination. If dirty, attempt careful cleaning with MAF sensor cleaner and a soft brush. If damaged or cleaning doesn't resolve the code, replace the MAF sensor.
- 3
Inspect and service fuel injectors
Have the fuel injectors on Bank 2 tested for proper spray pattern and flow. Replace any leaking or stuck injectors, or perform professional fuel injector cleaning if clogging is suspected.
- 4
Test and reprogram PCM if needed
If sensors and injectors test normal, perform a full PCM diagnostic using factory scan tools. If the PCM is confirmed faulty, reprogram it with the latest software or replace it if reprogramming fails.
Need a deeper diagnosis?
Search for related repair guides or browse by system.