OBD code P0301

Misfire detected on cylinder 1. The rest of the engine may run normally, but that cylinder is failing repeatedly.

Estimated severity

High

Common symptoms

Noticeable vibration at idle
Power loss, especially at low rpm
Higher fuel consumption
Possible smell of unburned fuel

Likely causes

Faulty spark plug on cylinder 1
Faulty ignition coil on cylinder 1
Dirty or blocked injector on cylinder 1
Loss of compression in that cylinder
Damaged connector or wiring specific to cylinder 1

Recommended checks

1. Use a scanner to confirm whether only P0301 is present or whether other misfire codes are also stored.
2. Inspect the spark plug on cylinder 1 and replace it if needed.
3. Swap the ignition coil from cylinder 1 with another cylinder and check whether the fault moves.
4. Check injector operation, including resistance, signal and possible cleaning.
5. Perform a compression test on cylinder 1 and compare it with the other cylinders.

What does code P0301 mean?

Code P0301 is a cylinder-specific misfire code. The ECU has detected that cylinder 1 is not burning the mixture correctly. This helps narrow the diagnosis to that cylinder, usually around the spark plug, ignition coil, injector or compression.

Try assisted diagnostics