P21A3
Cylinder 8 Air-Fuel Ratio Imbalance
P21A3 is an OBD-II diagnostic trouble code meaning: Cylinder 8 Air-Fuel Ratio Imbalance. Common causes: faulty injector of cylinder 8, problem with ignition coil or spark plug cylinder 8. Estimated repair cost: $17–89.
Symptoms
- Unstable engine idling
- Misfire in cylinder 8
- Loss of engine power
- Increased fuel consumption
- Check engine light comes on
Causes
- Faulty injector of cylinder 8
- Problem with ignition coil or spark plug cylinder 8
- Vacuum leak in the area of the intake manifold of cylinder 8
- Low compression in the eighth cylinder
- Problems with the oxygen sensor or its wiring
How to Fix
- Diagnostics and checking the condition of the spark plug and coil of cylinder 8
- Checking the performance of the fuel injector of cylinder 8
- Compression testing in the eighth cylinder
- Checking for vacuum leaks around the intake manifold
- Diagnostics of oxygen sensors and their wiring
Related codes
Error P21A3 by Vehicle Brand
FAQ
What does the P21A3 code mean?
P21A3 is an OBD-II diagnostic trouble code that indicates: Cylinder 8 Air-Fuel Ratio Imbalance
What causes a P21A3 error code?
The most common causes of P21A3 include: Faulty injector of cylinder 8; Problem with ignition coil or spark plug cylinder 8; Vacuum leak in the area of the intake manifold of cylinder 8; Low compression in the eighth cylinder.
How do I fix a P21A3 diagnostic trouble code?
To fix P21A3: Diagnostics and checking the condition of the spark plug and coil of cylinder 8. Checking the performance of the fuel injector of cylinder 8. Compression testing in the eighth cylinder. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21A3?
Limited driving only, diagnose soon
How much does it cost to fix P21A3?
The estimated repair cost for P21A3 is $17–89. Actual cost depends on your vehicle, location, and labor rates.
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