What does OBD2 code P0303 mean?
The engine control module (ECM) or powertrain control module (PCM) sets code P0303 when it registers that the Cylinder 3 Misfire Detected performance has fallen below the manufacturer's required baseline. This triggers your vehicle's malfunction indicator lamp (MIL), commonly known as the Check Engine Light.
Is It Safe to Drive with Code P0303?
No. Engine shaking and damage to the exhaust system may occur.
Symptoms of OBD2 Code P0303
Depending on your car model, symptoms for P0303 may vary. The most typical symptoms include:
- Vibration
- Sluggish throttle response
- Flashing dashboard light
What Causes Code P0303?
A variety of physical faults can trigger the P0303 code. Here are the most frequent culprits:
- Failed Cylinder 3 spark plug or ignition coil
- Fuel injector failure
- Compression failure
Step-by-Step Diagnostic Routine
Before replacing any expensive components, run through these standardized troubleshooting steps:
- Verify Cylinder 3 misfire in OBDAssistant.
- Perform ignition coil rotation diagnostic.
Expected Repair Costs for P0303
$60 - $200.
Save on Diagnosis with OBDAssistant
Isolates the fault to Cylinder 3 so you can test spark plugs and coil circuits.
Frequently Asked Questions
Yes, if Cylinder 3's injector cannot spray fuel, no combustion occurs, triggering the misfire.