TORQDEX // POWERTRAIN DTC
Cylinder 3 Misfire Detected
Misfire activity has been detected repeatedly on cylinder 3.
00 // CODE DEFINITION
What P0303 means
P0303 identifies a combustion problem occurring on cylinder 3.
The fault can originate from ignition, fuel delivery, compression, air leakage, wiring, or mechanical condition.
01 // COMMON SYMPTOMS
What you may notice
02 // COMMON CAUSES
What can trigger P0303?
Ignition fault
A weak plug, coil, wire, or electrical connection may cause the misfire.
Injector fault
Cylinder 3 may not be receiving the proper amount of fuel.
Mechanical fault
Low compression or valve-train problems may affect combustion.
03 // DRIVEABILITY
Can I keep driving with P0303?
Driving may be possible if the misfire is mild, but avoid continued driving if the check-engine light is flashing, the engine is shaking heavily, or power is significantly reduced. An active misfire can damage the catalytic converter.
04 // DIAGNOSTIC ORDER
Start here
Verify the affected cylinder
Review live misfire counters when available.
Check ignition components
Inspect and swap appropriate components to see whether the fault moves.
Check injector operation
Verify electrical and mechanical injector performance.
Check mechanical condition
Perform compression or leak-down testing if needed.
05 // COMMON REPAIR AREAS
Systems commonly involved
These are common areas associated with P0303. Testing should confirm the actual fault before parts are replaced.
Ignition fault
A weak plug, coil, wire, or electrical connection may cause the misfire.
Injector fault
Cylinder 3 may not be receiving the proper amount of fuel.
Mechanical fault
Low compression or valve-train problems may affect combustion.
06 // DIAGNOSTIC PRINCIPLE
Confirm the fault before replacing parts
P0303 identifies a condition detected by the vehicle control system. It does not automatically identify one failed component. Test the affected system before replacing parts.
07 // RELATED TORQDEX DIAGNOSTICS
Related diagnostic guides
Continue troubleshooting by symptom and system. These TorqDex guides cover common diagnostic paths associated with this trouble code.
08 // RELATED CODES