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
- Turn the ignition switch to ON (II).
- Clear the DTC with the HDS.
- Start the engine, and let it idle without load (in P or N).
- 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, then 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 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.
- 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 coils from the problem cylinder with those 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 an ignition coil connector (no misfire at this time). Check for poor connections or loose terminals at the ignition coils.
- Determine which cylinder had the misfire.
Does the misfire occur in the cylinder where the ignition coils were exchanged?
YES -Replace the faulty ignition coils (see IGNITION COIL REPLACEMENT ), then go to step 50.
NO -Go to step 14.
- Turn the ignition switch to LOCK (0).
- Exchange the spark plugs from the problem cylinder with those 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 plugs were exchanged?
YES -Replace the faulty spark plugs, then go to step 49.
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 50.
NO -Go to step 25.
- Turn the ignition switch to LOCK (0).
- Disconnect the ignition coil 3P connectors from the problem cylinder.
- Turn the ignition switch to ON (II).
- Measure the voltage between ignition coil 3P connector terminal No. 3 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 29.
NO -Repair an open in the wire between the ignition coil and the No. 2 INTAKE SIDE IGNITION COILS (15A) fuse (or the No. 1 EXHAUST SIDE IGNITION COILS (15A) fuse)*, then go to step 49.
*: exhaust side
- Turn the ignition switch to LOCK (0).
- Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Go to step 31.
NO -Repair an open in the wire between the ignition coil and G101 (see ENGINE WIRE HARNESS (ENGINE SECTION) ), then go to step 49.
*: exhaust side
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (44P).
- Check for continuity between body ground and the appropriate PCM connector terminal of the problem cylinder (see table).
FRONT (INTAKE) SIDE:
CONTINUITY SPECIFICATIONPROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C15 WHT No. 2 P0302 C16 WHT/GRN No. 3 P0303 C17 WHT/BLK No. 4 P0304 C18 WHT/BLU REAR (EXHAUST) SIDE:
CONTINUITY SPECIFICATIONPROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C23 WHT No. 2 P0302 C24 WHT/GRN No. 3 P0303 C25 WHT/BLK No. 4 P0304 C19 WHT/BLU Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Repair a short in the wire between the PCM and the ignition coil, then go to step 49.
NO -Go to step 34.
- Check for continuity between appropriate ignition coil 3P connector terminal No. 1 and the appropriate PCM connector terminal of the problem cylinder (see table).
FRONT (INTAKE) SIDE:
CONTINUITY SPECIFICATIONPROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C15 WHT No. 2 P0302 C16 WHT/GRN No. 3 P0303 C17 WHT/BLK No. 4 P0304 C18 WHT/BLU REAR (EXHAUST) SIDE:
CONTINUITY SPECIFICATIONPROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C23 WHT No. 2 P0302 C24 WHT/GRN No. 3 P0303 C25 WHT/BLK No. 4 P0304 C19 WHT/BLU Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Go to step 35.
NO -Repair an open in the wire between the PCM and the ignition coil, then go to step 49.
- Do an engine compression and a cylinder leak down test (see
ENGINE COMPRESSION INSPECTION
).
Did the engine pass both tests?
YES -Go to step 36.
NO -Repair the engine, then go to step 49.
- Do the VTEC rocker arm test (see
VTEC ROCKER ARM TEST
).
Did the engine pass the test?
YES -Go to step 37.
NO -Repair the VTEC rocker arm (see ROCKER ARM AND SHAFT DISASSEMBLY/REASSEMBLY ), then go to step 49.
- Turn the ignition switch to ON (II).
- Measure the voltage between body ground and the appropriate PCM connector terminal of the problem cylinder (see table).VOLTAGE SPECIFICATION
PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C5 BRN No. 2 P0302 C6 RED No. 3 P0303 C7 BLU No. 4 P0304 C8 YEL Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 43.
NO -Go to step 39.
- Turn the ignition switch to LOCK (0).
- Disconnect the injector 2P connector from the problem cylinder.
- Turn the ignition switch to ON (II).
- Measure the voltage between injector 2P connector terminal No. 1 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 43.
NO -Repair an open in the wire between the injector and PGM-FI main relay 1, then go to step 49.
- Turn the ignition switch to LOCK (0).
- Check for continuity between body ground and the appropriate PCM connector terminal of the problem cylinder (see table).CONTINUITY SPECIFICATION
PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C5 BRN No. 2 P0302 C6 RED No. 3 P0303 C7 BLU No. 4 P0304 C8 YEL Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Repair a short in the wire between the PCM and the injector, then go to step 49.
NO -Go to step 45.
- Check for continuity between appropriate injector 2P connector terminal No. 2 and the appropriate PCM connector terminal of the problem cylinder (see table).CONTINUITY SPECIFICATION
PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR No. 1 P0301 C5 BRN No. 2 P0302 C6 RED No. 3 P0303 C7 BLU No. 4 P0304 C8 YEL Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Replace the injector, then go to step 46.
NO -Repair an open in the wire between the PCM and the injector, then go to step 49.
- Turn the ignition switch to LOCK (0).
- Disconnect the injector 2P connector from the problem cylinder.
- At the injector side, measure the resistance between injector 2P connector terminals No. 1 and No. 2.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there 10-13 Ω?
YES -Go to step 57.
NO -Replace the injector (see INJECTOR REPLACEMENT ), then go to step 49.
- Reconnect all connectors.
- Turn the ignition switch to ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Do the CKP pattern learn procedure (see 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 coil, the injector, and the PCM, then go to the troubleshooting for DTC P0300, P0301, P0302, P0303, or P0304 (see DTC P0300: RANDOM MISFIRE AND ANY COMBINATION OF THE FOLLOWING: ).
NO -Go to step 56.
- 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 55, go to the indicated DTC's troubleshooting.
NO -If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the 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 54.
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
- 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 coil, the injector, and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 59. If the PCM was substituted, go to step 1.
NO -Go to step 61.
- 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 PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Pending or Confirmed DTCs were indicated in step 60, go to the indicated DTC's troubleshooting.
NO -If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 59. If the 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 59.