What does code P0304 mean on a Volvo and is it safe to drive?
P0304: Cylinder 4 Misfire Detected. Here's what it means on your Volvo, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
Misfire confirmed on cylinder 4. On 4-cylinder engines, this is the last cylinder—check coil and plug first, then injector, then compression.
Common causes for your Volvo
- Worn spark plug on cylinder 4
- Failed ignition coil on cylinder 4
- Faulty or clogged fuel injector
- Low compression or valve issue
Symptoms
- Check Engine Light
- Rough idle and shaking
- Poor acceleration or power loss
Typical fixes
- Replace spark plug and COP coil on cylinder 4
- Clean or replace fuel injector
- Compression and leak-down test if basic parts check out
Repair cost range
For a Volvo, repairs for P0304 often fall between $150 and $900, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Volvo
Volvo T5 P0304 on cylinder 4 typically indicates a coil cassette failure or a worn spark plug. Cylinder 4 is near the turbocharger on B5254T engines—the additional heat can accelerate spark plug and coil wear on this cylinder. Replace the plug and test the cassette.
Most commonly affected models