P21FB
Fuel Control System B Too Rich at Idle Bank 2
P21FB is an OBD-II diagnostic trouble code meaning: Fuel Control System B Too Rich at Idle Bank 2. Common causes: faulty bank 2 oxygen sensors, stuck or overfilled fuel injectors. Estimated repair cost: $17–89.
Symptoms
- Unstable engine idling
- Increased fuel consumption
- Black smoke from the exhaust pipe
- Loss of engine power
- Smell of unburned fuel
Causes
- Faulty Bank 2 oxygen sensors
- Stuck or overfilled fuel injectors
- Fuel pressure regulator malfunction
- Dirty or faulty mass air flow sensor (MAF)
- Intake manifold vacuum leaks
How to Fix
- Diagnosis and replacement of faulty oxygen sensors
- Checking and cleaning fuel injectors
- Fuel pressure regulator diagnostics
- Checking the mass air flow sensor and air temperature sensors
- Finding and Repairing Vacuum Leaks
Related codes
Error P21FB by Vehicle Brand
FAQ
What does the P21FB code mean?
P21FB is an OBD-II diagnostic trouble code that indicates: Fuel Control System B Too Rich at Idle Bank 2
What causes a P21FB error code?
The most common causes of P21FB include: Faulty Bank 2 oxygen sensors; Stuck or overfilled fuel injectors; Fuel pressure regulator malfunction; Dirty or faulty mass air flow sensor (MAF).
How do I fix a P21FB diagnostic trouble code?
To fix P21FB: Diagnosis and replacement of faulty oxygen sensors. Checking and cleaning fuel injectors. Fuel pressure regulator diagnostics. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21FB?
Limited driving only, diagnose soon
How much does it cost to fix P21FB?
The estimated repair cost for P21FB is $17–89. Actual cost depends on your vehicle, location, and labor rates.
See also: Russian version · NationStat