Error code

OBD2 P0301

OBD2P0301
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Cylinder 1 Misfire Detected.

Severity

moderateAvoid driving if possible to prevent further damage.

Summary

P0301 indicates a misfire detected in Cylinder 1 of the engine.

Symptoms

  • Engine shaking or jerking
  • Decreased fuel efficiency

Common Causes

  • Spark problem (ignition coil, spark plug)
  • Compression problem (worn piston rings, valve issues)
  • Fuel injection problem (injector malfunction or clogging)

Diagnosis

  1. Check ignition system for spark issues using a spark tester.
  2. Perform compression and leak down tests on Cylinder 1.
  3. Test fuel injectors with a noid light or multimeter.

Fixes

  • Replace faulty spark plug, ignition coil, or fuel injector.

FAQ

Can a bad O2 sensor cause a misfire in cylinder 1?

No, a bad oxygen (O2) sensor cannot directly cause a single-cylinder misfire.

How long does it take for a misfire to damage the catalytic converter?

A persistent misfire can quickly lead to catalyst damage if not addressed promptly.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

More OBD2 codes

All OBD2 codes →Search more codes →