DTC P0301-P0304: Cylinders No. 1-4 Misfire Detected
- Turn ignition off. Connect scan tool. Retrieve DTCs. If no other DTCs exist, go to next step. If DTCs P0101, P0102, P0103, P0116, P0117 or P0125 exist, diagnose affected DTCs. Do not diagnose misfire DTC.
- Clear ECM memory using scan tool. Start engine and drive vehicle for more than 10 minutes. If MIL illuminates or flashes, go to step 4. If MIL does not illuminate, go to next step.
- Determine if vehicle has run out of fuel in the recent past. If vehicle has run out of fuel, engine has no abnormality. Finish diagnostics operation. If vehicle has not been run out of fuel, check for abnormalities in ignition system including the following:
- Open Circuit Between ECM and Injectors
- Ignition Coil Connector
- Ignitor Connector
- Injector Connector
- ECM Connector B134
Repair as necessary. If ignition system is okay, finish diagnostics operation.
- Inspect air intake system for air leaks or air suction caused by loose or missing nuts or bolts. Check for cracks or loose connections of any hoses in system and repair as necessary. If no leaks are found, go to next step.
- Perform diagnosis according to items in SYMPTOM CHECK table.SYMPTOM CHECK
DTC Go To Step Only One Misfiring Cylinder "a" P0301 & P0302 "b" P0303 & P0304 "c" P0301 & P0303 "d" P0302 & P0304 "e" Random Misfire "f" Symptom Check Steps:
- "a" - Only One Cylinder
Check following items for that cylinder:- Spark plug.
- Spark plug wire.
- Fuel injector.
- Compression.
Repair or replace as needed. If no problems are found, go to step 6.
- "b" - Group Of Cylinders No. 1 & 2
Check following items for cylinders No. 1 and 2:- Spark plugs.
- Fuel injectors.
- Ignitors, ignition coils, etc.
Repair or replace as needed. If no problems are found, go to step 6.
- "c" - Group Of Cylinders No. 3 & 4
Check following items for cylinders No. 3 and 4:- Spark plugs.
- Fuel injectors.
- Ignitors, ignition coils, etc.
Repair or replace as needed. If no problems are found, go to step 6.
- "d" - Group Of Cylinders No. 1 & 3
Check following items for cylinders No. 1 and 3:- Spark plugs.
- Fuel injectors.
- Skipped/jumped timing belt teeth.
Repair or replace as needed. If no problems are found, go to step 6.
- "e" - Group Of Cylinders No. 2 & 4
Check following items for cylinders No. 2 and 4:- Spark plugs.
- Fuel injectors.
- Skipped/jumped timing belt teeth.
Repair or replace as needed. If no problems are found, go to step 6.
- "f" - Cylinder At Random
If engine idle is not rough, go to DTC P0170 and retest.
CAUTION: DO NOT use solvent when cleaning EGR valve assembly, as it can damage diaphragm. - "a" - Only One Cylinder
- If engine idle is rough, observe minimum EGR pressure display on scan tool. If EGR pressure is less than one kPa, clean EGR valve. Ensure valve operates smoothly and valve seat area is completely clean. Replace EGR valve if required. If EGR pressure value is more than one kPa, diagnose using DTC P0170 and retest.