DTC P0301: No. 1 Cylinder Misfire Detected DTC P0302: No. 2 Cylinder Misfire Detected DTC P0303: No. 3 Cylinder Misfire Detected DTC P0304: No. 4 Cylinder Misfire Detected

1. Note this freeze data:
   - Engine speed
   - Vehicle speed
   - Throttle position
   - CLV

1. Clear the DTC with the HDS.

1. Start the engine without load (in Park or neutral), then let it idle.

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 screen indicates PASSED, go to Step 5 . If the screen indicates EXECUTING, keep the driving condition continually until a result comes on. If the screen indicates OUT OF CONDITION, wait for several minutes and recheck.

1. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES | - | Go to Step 9 .
NO | - | Go to Step 6 .

1. Test-drive the vehicle for several minutes in the range of the recorded freeze data.

1. Monitor the OBD STATUS for DTC P0301, P0302, P0303 or P0304 in the DTCs MENU with the HDS.

Does the screen inidcated FAILED?

YES | - | Go to Step 9 .
NO | - | If the screen indicates PASSED, go to Step 8 . If the screen indicates EXECUTING, keep the driving condition continually until a result comes on. If the screen indicates OUT OF CONDITION, go to Step 6 and recheck.

1. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES | - | Go to Step 9 .
NO | - | Intermittent failure, system is OK at this time.■

1. Turn the ignition switch OFF.

1. Remove the intake manifold cover.

1. Start the engine, and listen for a clicking sound at the injector of the problem cylinder.

Does the injector click?

YES | - | Go to Step 12 .
NO | - | Go to Step 57 .

1. Turn the ignition switch OFF.

1. Exchange the ignition coil from the problem cylinder with one from another cylinder.

1. Test-drive the vehicle for several minutes in the range of the recorded freeze data.

1. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES | - | Go to Step 16 .
NO | - | Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time). Make sure the coil connections are secure.■

1. Determine which cylinder had the misfire.

Does the misfire occur in the cylinder where the ignition coil was moved?

YES | - | Replace the faulty ignition coil, then go to Step 62 .
NO | - | Go to Step 17 .

1. Turn the ignition switch OFF.

1. Exchange the spark plug from the problem cylinder with one from another cylinder.

1. Test-drive the vehicle for several minutes in the range of the recorded freeze data.

1. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES | - | Go to Step 21 .
NO | - | Intermittent misfire due to spark plug fouling (no misfire at this time).■

1. Determine which cylinder had the misfire.

Does the misfire occur in the cylinder where the spark plug was moved?

YES | - | Replace the faulty spark plug, then go to Step 62 .
NO | - | Go to Step 22 .

1. Turn the ignition switch OFF.

1. Exchange the injector from the problem cylinder with one from the another cylinder.

1. Start the engine, and let it idle 2 minutes.

1. Test-drive the vehicle for several minutes in the range of the recorded freeze data.

1. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES | - | Go to Step 27 .
NO | - | Intermittent misfire due to bad contact in the injector connector (no misfire at this time). Check for poor connections or loose terminals at the injector.■

1. Determine which cylinder had the misfire.

Does the misfire occur in the cylinder where the injector was moved?

YES | - | Replace the faulty injector, then go to Step 62 .
NO | - | Go to Step 28 .

1. Turn the ignition switch OFF.

1. Disconnect the ignition coil 3P connector from the problem cylinder.

1. Turn the ignition switch ON (II).

1. Measure voltage between ignition coil 3P connector terminal No. 3 and body ground.

Is there battery voltage?

YES | - | Go to Step 32 .
NO | - | Repair open in the wire between the ignition coil and the ignition coil relay, then go to Step 62 .

1. Turn the ignition switch OFF.