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Home >> Honda >> 2005 >> Odyssey EX >> Repair and Diagnosis >> Electrical >> Gauges >> Reminder Systems, Key Light Timer, And Engine Oil Pressure Indicator Systems >> Control Unit Input Test >> Multiplex Integrated Control Unit (MICU)
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Multiplex Integrated Control Unit (MICU)

  1. Turn the ignition switch OFF.
  2. Remove the left kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREAS ).
  3. Disconnect the driver's under-dash fuse/relay box connectors E, F, H, and P (see DRIVER'S UNDER-DASH FUSE/RELAY BOX ).
    NOTE: All connectors are wire side of female terminals.
    Fig 1: Identifying Driver's Under-Dash Fuse/Relay Box Connectors
    G03706831Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Inspect the connector and socket terminals to be sure they are all making good contact.
    • If the terminal are bent, loose or corroded, repair them as necessary, and recheck the system.
    • If the terminals look OK, go to step 5.
  5. With the connectors still disconnected, make the input tests shown in CONTROL UNIT INPUT TEST DESCRIPTION  , at the appropriate connectors on the driver's under-dash fuse/relay box.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, go to step 6.
    CONTROL UNIT INPUT TEST DESCRIPTION

    Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained
    P8 WHT/BLK Under all conditions Attach to ground:
    The ignition key light should come on.
    • Blown No. 13 (20 A) fuse in the under-hood fuse/relay box
    • Faulty ignition key light
    • An open in the wire
  6. Reconnect the connectors to the driver's under-dash fuse/relay box. Turn the ignition switch ON (II) and make the input tests shown in CONTROL UNIT INPUT TEST DESCRIPTION  , at the appropriate connectors on the driver's under-dash fuse/relay box.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, go to step 7.
    CONTROL UNIT INPUT TEST DESCRIPTION

    Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained
    E9 : H9 BLK Under all conditions Check for voltage to ground:
    There should be less than 1 V.
    • Poor ground(G601)
    • An open in the wire
    P14 BLK Under all conditions Check for voltage to ground:
    There should be less than 1 V.
    • Poor ground(G401)
    • An open in the wire
    F14 BLU/RED Driver's seat belt unbuckled Check for voltage to ground:
    There should be less than 1 V.
    • Faulty driver's seat belt switch
    • Poor ground(G602)
    • An open in the wire
        Driver's seat belt buckled Check for voltage to ground:
    There should be 5 V or more.
    • Faulty driver's seat belt switch
    • Short to ground
    P2 RED/WHT Ignition key in the ignition switch Check for voltage to ground:
    There should be less than 1 V.
    • Faulty ignition key switch
    • Poor ground(G502)
    • An open in the wire
        Ignition key out of the ignition switch Check for voltage to ground:
    There should be 5 V or more.
    • Faulty ignition key switch
    • Short to ground

    Gauge Control Module 

  7. Turn the ignition switch OFF.
  8. Remove the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).
  9. Disconnect the gauge control module connector A (30P).
    Fig 2: Identifying Gauge Control Module Connector A (30P)
    G03706832Courtesy of AMERICAN HONDA MOTOR CO., INC.
  10. Inspect the connector and socket terminals to be sure they are all making good contact.
    • If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
    • If the terminals look OK, go to step 11.
  11. With the connectors still disconnected, make the input tests shown in CONTROL UNIT INPUT TEST DESCRIPTION  , at the connector.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If the input tests prove OK, go to step 12.
    CONTROL UNIT INPUT TEST DESCRIPTION

    Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained
    A28 BLU/YEL Engine OFF Check for continuity to ground:
    There should be continuity.
    • Faulty engine oil pressure switch
    • An open in the wire
    Engine running Check for continuity to ground:
    There should be no continuity.
    • Mechanical problem in the engine
    • Faulty engine oil pressure switch
    • An open in the wire
    A20 : A21 BLK Under all conditions Check for continuity to ground:
    There should be continuity.
    • Poor ground(G502)
    • An open in the wire
  12. Reconnect the connectors at the driver's under-dash fuse/relay box and the gauge control module.
  13. Perform the Gauge Self-diagnostic Procedure (see SELF-DIAGNOSTIC FUNCTION ).
    • If the beeper sounds and the seat belt reminder light flashes, go to step 14.
    • If the beeper does not sound or the seat belt reminder light does not flash, replace the gauge control module.
  14. Substitute a known-good gauge control module and recheck the system.
    • If the symptom is gone, the gauge control module is faulty; replace it.
    • If the symptom is still present, the multiplex integrated control unit (MICU) is faulty; replace the driver's under-dash fuse/relay box.
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