What does code P21F5 mean?

Q: What does code P21F5 mean?

Fuel Control System B Too Rich Off Idle (Bank 1). P21F5 means the powertrain control module has detected that the fuel control system for Bank 1 is running too rich when the engine is off idle, meaning the exhaust contains more fuel than the computer commanded. The computer compares its calculated air-fuel ratio against feedback from the oxygen sensors and sets this code when the rich condition exceeds a calibrated threshold during off-idle operation.

DTC codes / P21xx · Fuel and air metering / P21F5

P21F5Fuel Control System B Too Rich Off Idle (Bank 1)

P21F5 means the powertrain control module has detected that the fuel control system for Bank 1 is running too rich when the engine is off idle, meaning the exhaust contains more fuel than the computer commanded. The computer compares its calculated air-fuel ratio against feedback from the oxygen sensors and sets this code when the rich condition exceeds a calibrated threshold during off-idle operation.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.