P21FB

Fuel Control System B Too Rich at Idle Bank 2

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–89 (est.)

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

P2177 P2178 P2187 P2188