( TF09EACK72100090301FAAT90 )
DTC Troubleshooting: P0301 (71), P0302 (72), P0303 (73), P0304 (74)
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
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch to ON (II).
  1. Clear the DTC with the HDS.
  1. Start the engine, and let it idle without load (A/T in P or N, M/T in neutral).
  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 idling until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, 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 the 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 these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP 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 screen indicates PASSED, go to Step 8 . If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, 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 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 loose wires or poor connections in the fuel system circuit.■
  1. Turn the ignition switch to LOCK (0).
  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 these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP 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.■
  1. Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the ignition coil was exchanged?
YES -
NO -
Go to Step 14 .
  1. Turn the ignition switch to LOCK (0).
  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 these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP 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).■
  1. 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 40 .
NO -
Go to Step 19 .
  1. Turn the ignition switch to LOCK (0).
  1. Exchange the injector from the problem cylinder with one from the another cylinder.
  1. Start the engine, and let it idle for 2 minutes.
  1. 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
  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.■
  1. Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the injector was exchanged?
YES -
NO -
Go to Step 25 .
Did the engine pass both tests?
YES -
Go to Step 26 .
NO -
Repair the engine, then go to Step 40 .
Did the engine pass the test?
YES -
Go to Step 27 .
NO -
  1. Turn the ignition switch to LOCK (0).
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector C (49P).
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage between body ground and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
    PROBLEM CYLINDER
    DTC
    ECM/PCM TERMINAL
    WIRE COLOR
    No. 1
    P0301
    C5
    BRN
    No. 2
    P0302
    C6
    RED
    No. 3
    P0303
    C7
    BLU
    No. 4
    P0304
    C8
    YEL

Is there battery voltage?
YES -
Go to Step 39 .
NO -
Go to Step 32 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage between injector 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to Step 36 .
NO -
Repair open in the wire between the injector and PGM-FI main relay 1, then go to Step 40 .
  1. Turn the ignition switch to LOCK (0).
  1. Check for continuity between body ground and the ECM/PCM connector terminal of the problem cylinder (see table).
    PROBLEM CYLINDER
    DTC
    ECM/PCM TERMINAL
    WIRE COLOR
    No. 1
    P0301
    C5
    BRN
    No. 2
    P0302
    C6
    RED
    No. 3
    P0303
    C7
    BLU
    No. 4
    P0304
    C8
    YEL

Is there continuity?
YES -
Repair short in the wire between the ECM/ PCM and the injector, then go to Step 40 .
NO -
Go to Step 38 .
  1. Check for continuity between appropriate injector 2P connector terminal No. 2 and the ECM/PCM connector terminal of the problem cylinder (see table).
    PROBLEM CYLINDER
    DTC
    ECM/PCM TERMINAL
    WIRE COLOR
    No. 1
    P0301
    C5
    BRN
    No. 2
    P0302
    C6
    RED
    No. 3
    P0303
    C7
    BLU
    No. 4
    P0304
    C8
    YEL

Is there continuity?
YES -
Go to Step 39 .
NO -
Repair open in the wire between the ECM/ PCM and the injector, then go to Step 40 .
  1. At the injector side, measure the resistance between injector 2P connector terminals No. 1 and No. 2.
Is there 10−13 Ω?
YES -
Go to Step 50 .
NO -
  1. Turn the ignition switch to LOCK (0).
  1. Reconnect all connectors, and install the parts in the reverse order of removal.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM/PCM with the HDS.
  1. Clear the CKP pattern with the HDS.
  1. 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
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0301, P0302, P0303, or P0304 indicated?
YES -
NO -
Go to Step 49 .
  1. 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 Temporary DTCs or DTCs were indicated in Step 48 , go to the indicated DTC's troubleshooting.■
NO -
If the screen 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 screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to Step 47 .
  1. Reconnect all connectors.
  1. 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
  1. Check for Temporary DTCs or 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. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 52 . If the ECM/PCM was substituted, go to Step 1 .
NO -
Go to Step 54 .
  1. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in Step 53 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 52 . If the ECM/PCM was substituted, go to Step 1 . If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to Step 52 .