Cylinder 3 Misfire Detected
P0303 — Cylinder 3 Misfire Detected
System: Powertrain | Type: Generic (OBD-II Standard) | Make: Generic
P0303 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.
Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.
Because P0303 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.
The P0303 fault code is set when the powertrain control module (PCM) detects a misfire in cylinder 3. This indicates that the air-fuel mixture in cylinder 3 is not combusting correctly, potentially causing rough engine performance, reduced fuel efficiency, or increased emissions.
Detailed possible causes for P0303 are available to TaT members.
Unlock with Free TrialStep-by-step diagnostic guidance for P0303 is available to TaT members. Our Diagnostic Assistant provides professional-level troubleshooting procedures written by experienced technicians.
Unlock with Free TrialA technical video for the P0303 fault code is available to TaT members.
Unlock with Free Trial| Code | P0303 |
| System | Powertrain |
| Type | Generic (OBD-II Standard) |
| Make | Generic |
| Causes | Available |
| Diag. Assistant | Available |
| Video | Available |
Get complete diagnostic info, causes, and repair guidance.
Start Free 7-Day Trial Member LoginSearch all 8,602 fault codes with complete diagnostic details, possible causes, and repair guidance.
Start Your Free 7-Day Trial Member Login© 2026 The Automotive Technician (TaT) — www.tat.net.au