P21FA

Fuel Control System B Too Lean at Idle Bank 2

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–111 (est.)

Symptoms

Unstable engine idling
Floating speed
Power Loss
Increased fuel consumption
Check engine light comes on

Causes

Air leaks in the intake tract after the mass air flow sensor
Malfunction of oxygen sensors (lambda probes)
Problems with the fuel pump or fuel pressure regulator
Dirty or faulty fuel injectors
Malfunction of the mass air flow sensor (MAF)

How to Fix

Check the intake system for air leaks
Check oxygen sensor readings
Measure the pressure in the fuel system
Clean or replace fuel injectors
Check the performance of the mass air flow sensor

Related codes

P2177 P2178 P2187