P21A0

Cylinder 5 Air-Fuel Ratio Imbalance

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–89 (est.)

Symptoms

Unstable engine idling
Increased fuel consumption
Loss of engine power
Misfire in cylinder 5
Check Engine Light Illuminates

Causes

Dirty or faulty fuel injectors
Air leak in the intake manifold
Problems with the ignition system (plugs, coils)
Oxygen sensor malfunction
Low compression in cylinder 5

How to Fix

Check the condition of the fuel injectors
Diagnose the ignition system of the 5th cylinder
Check the tightness of the intake tract
Test oxygen sensors
Measure compression in cylinders

Related codes

P21A1 P21A2 P21A3