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MICU Input Test

WARNING: This page is about a different car, the 2009 Acura MDX, 2008 Acura MDX, and 2007 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Before testing the MICU, troubleshoot the multiplex integrated control unit first, using B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A  ).
  1. Turn the ignition switch to LOCK (0).
  2. Remove the left kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREAS ).
  3. Disconnect under-dash fuse/relay box connectors D, E, F, G, H, J, N, P, Q, W, and X.
    NOTE: All connector views are wire side of female terminals.
    Fig 1: Identifying Under-Dash Fuse/Relay Box Connectors
    G05487865Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 2: Identifying Under-Dash Fuse/Relay Box Connectors
    G05487866Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. 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 5.
  5. With the connectors still disconnected, make these input tests at the connectors.
    • 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.
    INPUT TESTS REFERENCE

    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    D11 LT GRN Under all conditions (Under-hood fuse/relay box connector E (14P) disconnected) Check for continuity between the D11 terminal and the under-hood fuse/relay box connector E (14P) No. 1 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    G1 LT GRN Under all conditions (Rear fuse/ relay box connector B (34P) disconnected) Check for continuity between the G1 terminal and the rear fuse/relay box connector B (34P) Non terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    J4 LT GRN Under all conditions (Driver's MPCS unit connector A (40P) disconnected) Check for continuity between the J4 terminal and the driver's MPCS unit connector A (40P) No. 28 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    P6 LT BLU Under all conditions (MICU connector P (30P) disconnected) Check for continuity between the P6 terminal and the DLC Non terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    N22 LT GRN Under all conditions (Gauge control module connector A (12P) disconnected) Check for continuity between the N22 terminal and the gauge control module connector A (12P) No. 5 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    N28 LT GRN Under all conditions (Combination switch control unit 8P connector disconnected) Check for continuity between the N28 terminal and the combination switch control unit 8P connector No. 4 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    X27 LT GRN Under all conditions (Immobilizer-keyless control unit 7P connector disconnected) Check for continuity between the X27 terminal and the immobilizer-keyless control unit 7P connector No. 4 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    X27 GRY Under all conditions (Climate control unit 40P connector disconnected) Check for continuity between the X27 terminal and the climate control unit 40P connector No. 4 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    X27 LT GRN Under all conditions (Audio unit connector C (24P) disconnected) Check for continuity between the X27 terminal and the audio unit connector C (24P) No. 23 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
    X27 LT GRN Under all conditions (HandsFreeLink control unit 28P connector disconnected) Check for continuity between the X27 terminal and the HandsFreeLink control unit 28P connector No. 19 terminal:
    There should be continuity.    		 An open in the wire
    Check for continuity to ground:
    There should be no continuity.    		 A short to ground in the wire
  6. Reconnect the connectors, and make these input tests at the connectors.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, the MICU must be faulty; replace the under-dash fuse/relay box (see REMOVAL AND INSTALLATION ).
    INPUT TESTS REFERENCE

    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    E9 BLK Under all conditions Measure the voltage to ground:
    There should be less than 0.5 V.
    • Poor ground (G601)
    • An open in the wire
    H9
    O4
    P1 BRN Under all conditions Measure the voltage to ground:
    There should be less than 0.5 V.
    • Poor ground (G502)
    • An open in the wire
    F1 YEL Ignition switch ON (II) (Rear fuse/relay box connector B (34P) disconnected) Measure the voltage to ground:
    There should be battery voltage.
    • Blown No. 21 (7.5 A) fuse in the under-dash fuse/relay box
    • Faulty under-dash fuse/relay box
    • A short to ground in the wire between the MICU and rear fuse/relay box
    G3 WHT Under all conditions (Rear fuse/relay box connector B (34P) disconnected) Measure the voltage to ground:
    There should be battery voltage.
    • Blown No. 4 (40 A) fuse in the main under-hood fuse box
    • Blown No. 7 (10 A) fuse in the under-dash fuse/relay box
    • Faulty under-dash fuse/relay box
    • A short to ground in the wire between the MICU and rear fuse/relay box
    F14 ORN Under all conditions Short connection to ground:
    The ignition key light should come on.
    • Blown No. 4 (40 A) fuse in the main under-hood fuse box
    • Blown No. 6(7.5 A) fuse in the under-dash fuse/relay box
    • Faulty under-dash fuse/relay box
    • Faulty ignition key light
    • An open in the wire
    W4 LT GRN Under all conditions, (Interior lights switch in DOOR position) Short connection to ground:
    The interior lights should come on.
    • Blown No. 4 (40 A) fuse in the main under-hood fuse box
    • Blown No. 6 (7.5 A) fuse in the under-dash fuse/relay box
    • Faulty under-dash fuse/relay box
    • Blown map lights or ceiling light bulb(s)
    • An open in the wire
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