P03BC
Cylinder 4 Combustion Performance
P03BC is an OBD-II diagnostic trouble code meaning: Cylinder 4 Combustion Performance. Common causes: worn or dirty spark plug for cylinder 4, faulty ignition coil. Estimated repair cost: $22–333.
Symptoms
- Check Engine light on
- Deteriorating fuel economy
- Engine vibration, especially at idle
- Reduced engine power
- Black or blue smoke from the exhaust pipe
Causes
- Worn or dirty spark plug for cylinder 4
- Faulty ignition coil
- Clogged fuel injector
- Reduced compression (wear of rings, valves)
- Violation of valve timing
How to Fix
- Check the spark plug of cylinder 4 - visually and by measuring the gap
- Move the ignition coil from another cylinder to check
- Carry out a fuel system injector balance test
- Perform a compression test on cylinder 4
- Check valve timing using a data scanner
- Replace faulty components and reset error codes
Related codes
Error P03BC by Vehicle Brand
FAQ
What does the P03BC code mean?
P03BC is an OBD-II diagnostic trouble code that indicates: Cylinder 4 Combustion Performance
What causes a P03BC error code?
The most common causes of P03BC include: Worn or dirty spark plug for cylinder 4; Faulty ignition coil; Clogged fuel injector; Reduced compression (wear of rings, valves).
How do I fix a P03BC diagnostic trouble code?
To fix P03BC: Check the spark plug of cylinder 4 - visually and by measuring the gap. Move the ignition coil from another cylinder to check. Carry out a fuel system injector balance test. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P03BC?
Do not drive — repair immediately
How much does it cost to fix P03BC?
The estimated repair cost for P03BC is $22–333. Actual cost depends on your vehicle, location, and labor rates.
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