System Too Rich Off Idle Bank 1
Bank 1 fuel trim shows a strong rich correction during off-idle operation. The ECU is forced to subtract fuel to keep the mixture near stoichiometric.
Affected components
- Fuel pressure regulator
- Fuel injector
- Mass air flow sensor
- Evap purge valve
Common causes
- High likelihood: Leaking fuel injector
- Medium likelihood: Excessive fuel pressure
- Medium likelihood: Stuck-open purge valve
Possible symptoms
- Check engine light on
- Increased fuel consumption
- Black smoke from exhaust on acceleration
- Smell of unburned fuel, fouled spark plugs
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.