Powertrain
generic / SAE
P21F8
Fuel Control System B Too Lean at Idle (Bank 1)
Secondary fuel control loop B reports a lean condition at idle on bank 1. Idle is sensitive to vacuum leaks since manifold flow is low.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / F8
Possible causes
- Vacuum leak — most visible at idle high
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: 80–800 €
- Estimated time: 0.7–3.5 h
- Component: fuel injector
- Component: intake manifold
- Component: oxygen sensor
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012