What P0304 means
Diagnostic Trouble Code (DTC) P0304 stands for Cylinder 4 Misfire Detected. This is a generic OBD2 diagnostic trouble code indicating that the engine computer (ECU) has registered an operational anomaly in the powertrain (p) systems.
When this error registers, the ECU records a freeze frame of sensor data and lights up the Check Engine Light on your dashboard to notify the operator of a system fault.
Symptoms of OBD2 Code P0304
When code P0304 is active, your car might exhibit the following common symptoms:
- Engine sputter
- Poor acceleration
- Rough running
Common Causes of Code P0304
Faults that trigger this code typically include:
- Cause 1: Ignition coil failure on Cylinder 4
- Cause 2: Spark plug fouled on Cylinder 4
- Cause 3: Wiring connector loose
Can you drive with a P0304 code?
No. Avoid driving to prevent exhaust melting.
Expected Repair Cost Band
$60 - $200.
Related Diagnostic Trouble Codes
If you have scanned multiple codes, see these related guides for troubleshooting context:
Frequently Asked Questions
Usually a bad spark plug, failing ignition coil, or localized vacuum leak near Cylinder 4.