Fuel Control System B Too Lean Bank 1
Fuel control system B on bank 1 reports a persistently lean condition. Long-term fuel trim is at the positive limit, indicating insufficient fuel delivery or unmetered air ingress.
Affected components
- Fuel injectors
- Fuel pressure regulator
- Intake system
Common causes
- High likelihood: Vacuum leak downstream of MAF
- Medium likelihood: Fuel rail pressure low
Possible symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
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.