Quick Diagnosis Guide
Meaning: Code P0303 indicates that the vehicle's onboard computer (ECU) has registered a fault in the powertrain (p) circuits.
Can I still drive? No. Engine shaking and damage to the exhaust system may occur.
What does the P0303 code mean?
Diagnostic Trouble Code (DTC) P0303 stands for Cylinder 3 Misfire Detected. This is a generic OBD-II trouble code indicating that the ECU has detected system performance parameters that fall outside normal calibrated tolerances.
When this code is logged, the ECU illuminates the dashboard check engine light and triggers a freeze frame record of engine sensor values to help diagnose the issue.
Common Symptoms of Code P0303
Depending on the vehicle make and driving conditions, you may observe the following symptoms:
- Vibration
- Sluggish throttle response
- Flashing dashboard light
What causes the P0303 fault code?
Root causes for a P0303 code typically include:
- Potential Cause 1: Failed Cylinder 3 spark plug or ignition coil
- Potential Cause 2: Fuel injector failure
- Potential Cause 3: Compression failure
Repair Database Status
No verified vehicle-specific workshop fix is currently logged in our mobile mechanic database for this code. Refer to the diagnostic checklist below to isolate the fault.
Step-by-Step Diagnostic & Inspection Checklist
To inspect and troubleshoot a P0303 code, mechanics follow these validation steps:
- Step 1: Verify Cylinder 3 misfire in OBDAssistant.
- Step 2: Perform ignition coil rotation diagnostic.
Estimated Repair Cost Band
$60 - $200.
Note: Repair estimates vary based on vehicle make, model, local labor rates, and whether you require a full parts replacement.
Related Trouble Codes
If your scan tool registers other codes, check out these related guides:
Frequently Asked Questions
Yes, if Cylinder 3's injector cannot spray fuel, no combustion occurs, triggering the misfire.