DTC P0301, P0302, P0303, P0304: No. 1 Cylinder Misfire Detected; No. 2 Cylinder Misfire Detected; No. 3 Cylinder Misfire Detected; No. 4 Cylinder Misfire Detected ('11-12)
- Turn the ignition switch to ON (II).
- Clear the DTC with the HDS.
- Start the engine, and let it idle without load (A/T in P or N, M/T in neutral).
- Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES: Go to step 9.
NO: If the HDS indicates PASSED, go to step 5. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION or NOT COMPLETED, wait for several minutes, and recheck.
- Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE show misfire counts?
YES: Go to step 9.
NO: Go to step 6.
- Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- APP SENSOR
- ECT SENSOR 1
- Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES: Go to step 9.
NO: If the HDS indicates PASSED, go to step 8. If the HDS indicates EXECUTING, keep driving until a result comes on. If the HDS indicates OUT OF CONDITION or NOT COMPLETED, go to step 6 and recheck.
- Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE show misfire counts?
YES: Go to step 9.
NO: Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals in the fuel system circuit.
- Turn the ignition switch to LOCK (0).
- Exchange the ignition coil from the problem cylinder with one from another cylinder.
- Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- APP SENSOR
- ECT SENSOR 1
- Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE show misfire counts?
YES: Go to step 13.
NO: Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time). Check for poor connections or loose terminals at the ignition coil.
- Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the ignition coil was exchanged?
YES: Replace the faulty ignition coil (see IGNITION COIL REMOVAL/INSTALLATION ), then go to step 27 .
NO: Go to step 14.
- Turn the ignition switch to LOCK (0).
- Exchange the spark plug from the problem cylinder with one from another cylinder.
- Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- APP SENSOR
- ECT SENSOR 1
- Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE show misfire counts?
YES: Go to step 18.
NO: Intermittent misfire due to spark plug fouling (no misfire at this time).
- Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the spark plug was exchanged?
YES: Replace the faulty spark plug, then go to step 27 .
NO: Go to step 19.
- Turn the ignition switch to LOCK (0).
- Exchange the injector from the problem cylinder with one from the another cylinder.
- Start the engine, and let it idle for 2 minutes.
- Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- APP SENSOR
- ECT SENSOR 1
- Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE show misfire counts?
YES: Go to step 24.
NO: Intermittent misfire due to bad contact at the injector connector (no misfire at this time). Check for poor connections or loose terminals at the injector.
- Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the injector was exchanged?
YES: Replace the faulty injector (see INJECTOR REPLACEMENT ), then go to step 27 .
NO: Go to step 25.
- Do an engine compression and a cylinder leakdown test (see ENGINE COMPRESSION INSPECTION
).
Did the engine pass both tests?
YES: Go to step 26.
NO: Repair the engine, then go to step 27 .
- Do the VTEC rocker arm test (see VTEC ROCKER ARM TEST
).
Did the engine pass the test?
YES: Check for wear or damage to these parts listed. If needed, repair or replace part(s), then go to step 27.
- Cylinder head
- Carbon in the intake manifold
- Valve seal Piston ring
- Intake and exhaust valve
- Cam chain
- Valve guide
- Piston
NO: Repair the VTEC rocker arm (see ROCKER ARM ASSEMBLY REMOVAL ), then go to step 27 .
- Turn the ignition switch to LOCK (0).
- Install the parts in the reverse order of removal.
- Turn the ignition switch to ON (II).
- Reset the ECM/PCM with the HDS.
- Do ECM/PCM IDLE LEARN PROCEDURE .
- Do CKP PATTERN CLEAR/CKP PATTERN LEARN .
- Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- APP SENSOR
- ECT SENSOR 1
- Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0301, P0302, P0303, or P0304 indicated?
YES: Check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM, then go to the troubleshooting for DTC P0300, P0301, P0302, P0303, or P0304 (see DTC P0300, P0301, P0302, P0303, P0304: RANDOM MISFIRE AND ANY COMBINATION OF THE FOLLOWING: NO. 1 CYLINDER MISFIRE DETECTED; NO. 2 CYLINDER MISFIRE DETECTED; NO. 3 CYLINDER MISFIRE DETECTED; NO. 4 CYLINDER MISFIRE DETECTED ).
NO: Go to step 35.
- Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES: Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 34, go to the indicated DTC's troubleshooting.
NO: If the HDS indicates FAILED, check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM, then go to step 1. If the HDS indicates EXECUTING, keep driving until a result comes on. If the HDS indicates OUT OF CONDITION or NOT COMPLETED, go to step 33.