BMW DTC P21F6 – Fuel Control System ‘B’ Too Lean Off Idle (Bank 2)
DTC P21F6 meaning on BMW
The DTC P21F6 code on a BMW indicates an issue with the Fuel Control System ‘B’ being too lean off idle in Bank 2. This means that the engine control module (ECM) has detected a lean air-fuel mixture condition when the vehicle is not idling. The ECM monitors the air-fuel ratio to ensure optimal combustion and performance.
BMW DTC P21F6 symptoms
Symptoms of the DTC P21F6 code on a BMW may include:
- Check Engine Light illuminated
- Decreased fuel efficiency
- Engine hesitation or misfires
- Rough idle or stalling
BMW DTC P21F6 causes
Common causes of the DTC P21F6 code on a BMW include:
- Vacuum leaks in the intake system
- Faulty oxygen sensor
- Dirty or clogged fuel injectors
- Fuel pressure regulator issues
- Exhaust leaks
BMW DTC P21F6 seriousness
Ignoring the DTC P21F6 code on a BMW can lead to potential engine damage and decreased fuel efficiency. It is important to address this issue promptly to prevent further complications and ensure the vehicle operates optimally.
How to diagnose DTC P21F6 on BMW
To diagnose the DTC P21F6 code on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the fault codes
- Inspect the intake system for vacuum leaks
- Check the oxygen sensor readings
- Clean or replace fuel injectors if necessary
- Test the fuel pressure regulator
How to fix DTC P21F6 on BMW
To fix the DTC P21F6 code on a BMW, the following steps may be taken:
- Repair any vacuum leaks in the intake system
- Replace a faulty oxygen sensor
- Clean or replace clogged fuel injectors
- Address any fuel pressure regulator issues
- Clear the fault codes and reset the ECM
How to erase DTC P21F6 on BMW
To erase the DTC P21F6 code on a BMW, a diagnostic scanner can be used to clear the fault codes stored in the ECM. Once the repairs have been made and the issue resolved, the fault codes can be reset to turn off the Check Engine Light and ensure the vehicle is operating correctly.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.