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.
Medium severity. Can I keep driving?You can drive in moderation for a short time. A very lean or very rich mixture can damage the engine or the catalytic converter.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
Symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
Most likely causes
- Vacuum leak downstream of MAF
- Fuel rail pressure low
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2BF0 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- B: Subsystem depends on the code range
- F0: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2BF0?
You can drive in moderation for a short time. A very lean or very rich mixture can damage the engine or the catalytic converter.
What causes code P2BF0?
The most common causes are: vacuum leak downstream of MAF; fuel rail pressure low.
Related codes
- P2BEEFuel Control System A Too Lean Bank 2
- P2BF2Fuel Control System B Too Lean Bank 2
- P2BECFuel Control System A Too Lean Bank 1
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.