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Home >> Acura >> 2002 >> 3.2CL Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0301, P0302, P0303, P0304, P0305 Or P0306: Misfire In One Cylinder >> MDX

DTC P0301, P0302, P0303, P0304, P0305 Or P0306: Misfire In One Cylinder: MDX

  1. Remove intake manifold cover and ignition coil cover. Check and record freeze data. Perform PCM reset procedure and clear DTC(s). See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine and listen for clicking sound from fuel injector in suspect cylinder. If injector clicks, go to next step. If injector does not click, check for open or short in harness between suspect fuel injector 3-pin harness connector and PCM harness connectors. See WIRING DIAGRAMS article. If click is heard, go to next step. If click is not heard, go to step  12 .
  2. Turn ignition switch off and reset PCM. See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Remove ignition coil cover. Exchange ignition coil from suspect cylinder with one from another cylinder. Connect scan tool and start engine. Let engine idle for two minutes. Test drive vehicle several times under various conditions or freeze data range. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is set, go to next step. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is not set, problem is intermittent, possibly due to ignition coil fouling. If misfire followed ignition coil that was exchanged, replace ignition coil. If misfire stayed in same cylinder, go to next step.
  3. Turn ignition switch off and reset PCM. See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Exchange spark plug from suspect cylinder with one from another cylinder. Test drive vehicle several times in freeze data range or under various conditions if freeze data is not recorded. If DTCs P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is set, go to next step. If DTCs P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is not set, problem is intermittent, possibly due to fouling spark plug. Misfire is not detected at this time.
  4. Determine which cylinder had misfire. If misfire remains in same cylinder, go to next step. If misfire followed exchanged spark plug to different cylinder, replace spark plug.
  5. Turn ignition switch off and reset PCM. See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Exchange fuel injector from suspect cylinder with one from another cylinder. Start engine and let idle for 2 minutes. Test drive vehicle several times in freeze data range or under various conditions if freeze data is not recorded. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is set, go to next step. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is not set, problem is intermittent, possible intermittent or poor fuel injector connection.
  6. Determine which cylinder had misfire. If misfire remains in same cylinder, go to next step. If misfire followed exchanged fuel injector, replace faulty fuel injector. See FUEL RAILS & INJECTORS under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
  7. Turn ignition switch off. Disconnect ignition coil 3-pin harness connector from suspect cylinder. See Fig 1 . Turn ignition switch back on. Measure voltage between ground and ignition coil 3-pin harness connector terminal No. 3 (Black/Yellow wire). If battery voltage is present go to next step. If battery voltage is not present, repair open or short in Black/Yellow wire between ignition coil 3-pin harness connector terminal No. 3 and No. 11 IG COIL fuse (15-amp) in driver's under-dash fuse/relay box. See WIRING DIAGRAMS article. Repair as necessary.
    Fig 1: Identifying 3-Pin Ignition Coil Connector (MDX)
    G00032248Courtesy of AMERICAN HONDA MOTOR CO., INC.
  8. Turn ignition switch off. Check for continuity between ground and ignition coil 3-pin harness connector terminal No. 2 (Black wire). See Fig 1 . If continuity is present, go to next step. If continuity is not present, repair open in Black wire between ground and ignition coil 3-pin harness connector terminal No. 2.
  9. Disconnect PCM 31-pin harness connector. Check for continuity between ground and appropriate PCM 31-pin harness connector terminal. See DTC/PCM 31-PIN CONNECTOR TERMINAL IDENTIFICATION  table. If continuity is not present, go to next step. If continuity is present, repair short in appropriate wire between PCM 31-pin harness connector and suspect ignition coil 3-pin harness connector.
    DTC/PCM 31-PIN CONNECTOR TERMINAL IDENTIFICATION

    Suspect Cylinder DTC PCM Terminal No. Wire Color
    No. 1 P0301 4 Yellow/Light Green
    No. 2 P0302 14 Blue/Red
    No. 3 P0303 3 White/Blue
    No. 4 P0304 13 Brown
    No. 5 P0305 12 Black/Red
    No. 6 P0306 23 Brown/White
  10. Connect fused jumper wire between ground and suspect ignition coil 3-pin harness connector terminal No. 1. See Fig 1 . See DTC/IGNITION COIL 3-PIN CONNECTOR TERMINAL IDENTIFICATION  table. Check for continuity between ground and appropriate PCM 31-pin harness connector terminal. See DTC/PCM 31-PIN CONNECTOR TERMINAL IDENTIFICATION  table. If continuity is present, go to next step. If continuity is not present, repair open wire between PCM 31-pin harness connector and ignition coil 3-pin harness connector. See WIRING DIAGRAMS article. Repair as necessary.
    DTC/IGNITION COIL 3-PIN CONNECTOR TERMINAL IDENTIFICATION

    Suspect Cylinder DTC Wire Color
    No. 1 P0301 Yellow/Light Green
    No. 2 P0302 Blue/Red
    No. 3 P0303 White/Blue
    No. 4 P0304 Brown
    No. 5 P0305 Black/Red
    No. 6 P0306 Brown/White
  11. Check engine compression. See PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. If compression is okay, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM. If compression is not okay, repair engine as necessary. See appropriate appropriate article in ENGINES.
  12. Turn ignition switch off. Disconnect PCM 25-pin harness connector. Turn ignition switch on. Measure voltage between ground and appropriate PCM 25-pin harness connector terminal. See DTC/PCM 25-PIN CONNECTOR TERMINAL IDENTIFICATION  table. If battery voltage is present, go to next step. If battery voltage is not present, go to step  16 .
    DTC/PCM 25-PIN CONNECTOR TERMINAL IDENTIFICATION

    Suspect Cylinder DTC PCM Terminal Wire Color
    No. 1 P0301 11 Brown
    No. 2 P0302 5 Red
    No. 3 P0303 15 Blue
    No. 4 P0304 4 Yellow
    No. 5 P0305 3 Black/Red
    No. 6 P0306 6 White/Blue
  13. Disconnect fuel injector 2-pin harness connector on suspect cylinder. Measure resistance between fuel injector terminals No. 1 and 2. If resistance reading is 13-15 ohms, go to next step. If resistance reading is not 13-15 ohms, replace fuel injector.
  14. Exchange fuel injector from suspect cylinder with one from another cylinder. Start engine and let idle for 2 minutes. Test drive vehicle several times in freeze data range or under various conditions if there is no freeze data recorded. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is set, go to next step. If DTC P0301, P0302, P0303, P0304, P0305, P0306 or temporary DTC P1399 is not set, misfire condition is not detected at this time. Possible intermittent fuel injector poor connection.
  15. Determine which cylinder has misfire. If misfire follows injector to another cylinder, replace faulty fuel injector. See FUEL RAILS & INJECTORS under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If misfire remains in same cylinder, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  16. Turn ignition switch off. Disconnect fuel injector 2-pin harness connector from suspect cylinder. Measure voltage between ground and fuel injector 2-pin harness connector terminal No. 1 (Yellow/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, check for open in Yellow/Black wire between PGM-FI main relay 7-pin harness connector terminal No. 6 and fuel injector 2-pin harness connector terminal No. 1. See WIRING DIAGRAMS article. Repair as necessary.
  17. Turn ignition switch off. Check for continuity between ground and PCM 25-pin harness connector terminal(s). See DTC/PCM 25-PIN CONNECTOR TERMINAL IDENTIFICATION  table. If continuity is not present, go to next step. If continuity is present, repair short in wiring between PCM 25-pin harness connector and fuel injector 2-pin harness connector.
  18. Connect fused jumper wire between ground and appropriate fuel injector 2-pin harness connector terminal No. 2. See DTC/FUEL INJECTOR TERMINAL IDENTIFICATION  table. Check for continuity between ground and PCM 25-pin harness connector terminal(s). See DTC/PCM 25-PIN CONNECTOR TERMINAL IDENTIFICATION  table. If continuity is present, replace fuel injector. If continuity is not present, repair open wire between PCM 25-pin harness connector and fuel injector 2-pin harness connector terminal No. 2.
    DTC/FUEL INJECTOR TERMINAL IDENTIFICATION

    Suspect Cylinder DTC Wire Color
    No. 1 P0301 Brown
    No. 2 P0302 Red
    No. 3 P0303 Blue
    No. 4 P0304 Yellow
    No. 5 P0305 Black/Red
    No. 6 P0306 White/Blue
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