Powertrain
generic / SAE
P21FC
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.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / FC
Possible causes
- Fuel pressure drops under load high
- Charge-air leak after turbo medium
Symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–1500 €
- Estimated time: 0.7–5 h
- Component: fuel pressure regulator
- Component: fuel injector
- Component: charge air pipe
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012