P0302 serious

Cylinder 2 Misfire Detected

What does P0302 mean?

The P0302 code means the vehicle's onboard diagnostic system has detected: Cylinder 2 Misfire Detected. This is a serious severity code.

Common Symptoms

  • Rough idle
  • Flashing or steady Check Engine Light
  • Loss of power
  • Fuel smell from exhaust

Probable Causes (Ranked by Likelihood)

  • Faulty spark plug on cylinder 2 Very High
  • Failed ignition coil on cylinder 2 High
  • Clogged fuel injector on cylinder 2 High
  • Low compression on cylinder 2 Moderate

Step-by-Step Diagnostic Procedure

  1. Swap the cylinder 2 coil with an adjacent cylinder. If the misfire code changes cylinder numbers, replace the coil.

  2. Inspect and replace the spark plug on cylinder 2.

  3. Test fuel injector on cylinder 2 for correct resistance and spray pattern.

  4. Perform a compression test if coil and spark plug swaps do not resolve the misfire.

Frequently Asked Questions

Can a bad spark plug wire cause P0302?

Yes, on older vehicles with plug wires. Modern vehicles with coil-on-plug systems do not have wires. Test the wire resistance (should be under 10,000 ohms per foot) or swap it with another cylinder to test.

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