Code result
P21F9
Fuel Control System B Too Rich at Idle
Moderate severity
What it means
Fuel Control System B Too Rich at Idle (Bank 1): the fuel-trim control is correcting for an over-rich mixture in this operating range.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Injectors leak at low duty cycle
highOne of the most commonly reported causes for this code — check this first.
Related help
Get the full diagnosis
Add your vehicle and see step-by-step repair help, recalls, and TSBs in Wrenchify.
Diagnose P21F9 freeNo credit card required