P0305 - Cylinder 5 Misfire Detected
P0305 is a generic powertrain diagnostic trouble code indicating Cylinder 5 Misfire Detected. It relates to the Ignition System / Misfire system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Ignition System / Misfire |
| Fault Index | 05 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0305 mean?
The powertrain control module has detected that cylinder number 5 is misfiring, meaning combustion is failing in this cylinder.
Severity Level & Driveability Details
Severity: High
Misfires allow unburned fuel to flood the exhaust system, destroying the catalytic converter. Flashing light indicates active misfire.
Common Symptoms of P0305
- Engine vibration and sluggish acceleration.
- Rough idle and shaking.
- Raw fuel smell from the exhaust pipe due to Cylinder 5 misfire.
- Flashing malfunction indicator lamp on your dashboard.
Typical Causes for P0305
- Bad cylinder 5 spark plug.
- Failed cylinder 5 ignition coil.
- Failing fuel injector on cylinder 5.
- Low compression in cylinder 5.
Diagnostic and Troubleshooting Steps
Swap the cylinder 5 ignition coil with cylinder 4. If the misfire moves to cylinder 4 (P0304), the coil is defective. If not, inspect the spark plug, injector pulse, and check compression.
Typical Repairs and Fixes
- Replacing the ignition coil or spark plug for cylinder 5.
- Replacing the cylinder 5 fuel injector.
- Repairing internal cylinder leaks.
Sensor Location & Parts Involved
The ignition coil and spark plug for cylinder 5 are located on top of the cylinder head on the engine block.
Clearing Code & Recurrence
Resolve the underlying ignition or fuel fault in cylinder 5, then reset the codes using an OBD2 scanner.
Emissions & Smog Inspection Impact
Misfiring in cylinder 5 releases unburned hydrocarbons into the exhaust stream, potentially damaging the catalytic converter and raising emissions.
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Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- NHTSA Recall Database
- EPA OBD II Regulations
Frequently Asked Questions about P0305
What does the cylinder 5 misfire code P0305 mean?
The engine control module logged P0305 after detecting a combustion misfire in cylinder 5. This indicates that the fuel-air mixture is failing to ignite properly inside the cylinder 5 chamber.
Is it safe to drive with the cylinder 5 misfire code P0305 active?
No, driving with active misfires in cylinder 5 can ruin the catalytic converter.
How much does it cost to repair a cylinder 5 misfire code P0305 fault?
Replacing an ignition coil or spark plug for cylinder 5 typically costs $100-$300. Replacing the fuel injector for cylinder 5 costs $200-$450.
What are the common causes of the cylinder 5 misfire code P0305?
Trigger conditions for the cylinder 5 misfire code P0305 include: A worn or fouled spark plug in cylinder 5., Failed ignition coil or damaged spark plug wire for cylinder 5., Faulty fuel injector or poor fuel atomization in cylinder 5..
Can I clear the check engine light for cylinder 5 misfire code P0305?
Resolve the underlying ignition or fuel fault in cylinder 5, then reset the codes using an OBD2 scanner.
Will the cylinder 5 misfire code P0305 cause an inspection failure?
Misfiring in cylinder 5 releases unburned hydrocarbons into the exhaust stream, potentially damaging the catalytic converter and raising emissions.