What are the common causes of P2BF2?

A vacuum or intake leak on bank 2. Weak fuel delivery to the bank 2 injectors. Dirty or failing bank 2 injectors. An exhaust leak upstream of the bank 2 oxygen sensor. A faulty bank 2 upstream oxygen sensor.

Smoke test the intake for leaks on bank 2. Read bank 2 fuel trims at idle and at cruise. Check fuel pressure and injector flow on bank 2. Inspect for exhaust leaks before the bank 2 sensor. Test the bank 2 upstream oxygen sensor response. Clear the code and retest after repairs.

P2BF2

Fuel Control System B Too Lean Bank 2

System: Powertrain control (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P2BF2 means Fuel Control System B Too Lean Bank 2.

Check these first

A vacuum or intake leak on bank 2
Weak fuel delivery to the bank 2 injectors
Dirty or failing bank 2 injectors
An exhaust leak upstream of the bank 2 oxygen sensor
A faulty bank 2 upstream oxygen sensor

What to do next

Smoke test the intake for leaks on bank 2
Read bank 2 fuel trims at idle and at cruise
Check fuel pressure and injector flow on bank 2
Inspect for exhaust leaks before the bank 2 sensor
Test the bank 2 upstream oxygen sensor response
Clear the code and retest after repairs

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Updated

Generic SAE J2012 definition. Last updated 2026-08-30.