Fuel Control System B Too Lean at Higher Load (Bank 1)
Secondary fuel control loop B on bank 1 reports a lean condition at higher load. Lean at high load typically points at fuel pressure shortfall, restricted injectors, or charge-air leak.
Affected components
- Fuel pressure regulator
- Fuel injector
- Charge air pipe
Common causes
- High likelihood: Fuel pressure drops under load
- Medium likelihood: Charge-air leak after turbo
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
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.