P0304

Test 1 - 4:

Test 5 - 7:

Test 8 - 11:

Test 12 - 15:

Test 16 - 17:

Test 18:

SYMPTOM
P0304-CYLINDER #4 MISFIRE

TEST NOTE
This symptom is diagnosed using the test P0300-MULTIPLE CYLINDER MISFIRE.

WHEN MONITORED
Any time the engine is running, and the Target Learning Coefficient has been successfully updated.

SET CONDITION
When more than a 1.8% misfire rate is measured during two trips, or with a 10% to 30% misfire rate during one trip.

POSSIBLE CAUSES
- Intermittent misfire
- Visual and physical inspection
- Ignition wire
- ASD relay output circuit (coil)
- Engine mechanical problem
- Ignition coil
- Coil control circuit
- Spark plug
- Checking fuel pressure
- Fuel pump inlet strainer plugged
- Restricted fuel supply line
- Fuel pump module
- Checking fuel leak down
- Fuel injector operation
- ASD relay output circuit (injector)
- Fuel injector
- Injector control circuit
- PCM (ignition system)
- PCM