P0303
High Severity

P0303 — Cylinder 3 Misfire Detected

System: Emissions

What P0303 means

Diagnostic Trouble Code (DTC) P0303 stands for Cylinder 3 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 P0303

When code P0303 is active, your car might exhibit the following common symptoms:

  • Vibration
  • Sluggish throttle response
  • Flashing dashboard light

Common Causes of Code P0303

Faults that trigger this code typically include:

  • Cause 1: Failed Cylinder 3 spark plug or ignition coil
  • Cause 2: Fuel injector failure
  • Cause 3: Compression failure

Can you drive with a P0303 code?

No. Engine shaking and damage to the exhaust system may occur.

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

Will a bad fuel injector cause P0303?

Yes, if Cylinder 3's injector cannot spray fuel, no combustion occurs, triggering the misfire.