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Control Unit Input Test

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Before testing, troubleshoot the multiplex integrated control unit first, using B-CAN system Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

MICU 

  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 E, F, H, K, N, Q, and P.
    NOTE: All connector views are wire side of female terminals.
    Fig 1: Identifying Under-Dash Fuse/Relay Box Connectors
    G08055252Courtesy of AMERICAN HONDA MOTOR CO., INC.

    *: Connector view shown rotated 180° from actual position in the under-dash fuse/relay box.

  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, do the following input tests:
    • 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.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    E2 BRN Connect battery power to E2 (E8) terminal, and E8 (E2) terminal to body ground. Check actuator operation: The left and right rear door lock actuators should LOCK (UNLOCK).
    • Faulty left rear door lock actuator
    • Faulty right rear door lock actuator
    • An open or high resistance in the wire
    E8 GRY
    K2 GRY Connect battery power to K12(K2) terminal, and K2 (K12) terminal to body ground. Check actuator operation: The driver's door lock actuator should LOCK (UNLOCK).
    • Faulty driver's door lock actuator
    • An open or high resistance in the wire
    K12 BRN
    N7 BRN Connect battery power to N7(N9) terminal, and N9 (N7) terminal to body ground. Check actuator operation: The front passenger's door lock actuator should LOCK (UNLOCK).
    • Faulty front passenger's door lock actuator
    • An open or high resistance in the wire
    N9 GRY
  6. Reconnect the remaining connectors, then turn the ignition switch to ON (II), and do the following input tests:
    • 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.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    P1 BRN In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G502) or an open in the ground wire
    • An open or high resistance in the wire
    E9 BLK In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • An open or high resistance in the wire
    H9
    Q4
    E15 GRN Driver's door open Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty driver's door switch
    • Faulty driver's door switch ground
    • An open or high resistance in the wire
    Driver's door closed Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty driver's door switch
    • A short to ground in the wire
    H12 LT GRN Front passenger's door open Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty front passenger's door switch
    • Faulty front passenger's door switch ground
    • An open or high resistance in the wire
    Front passenger's door closed Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty front passenger's door switch
    • A short to ground in the wire
    Q2 GRY Right rear door open Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty right rear door switch
    • Faulty right rear door switch ground
    • An open or high resistance in the wire
    Right rear door closed Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty right rear door switch
    • A short to ground in the wire
    Q8 GRN Left rear door open Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty left rear door switch
    • Faulty left rear door switch ground
    • An open or high resistance in the wire
    Left rear door closed Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty left rear door switch
    • A short to ground in the wire
    P12 GRY In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty connection at the audio unit, navigation display unit, and/or rear controller and screen
    • Faulty audio unit
    • Faulty navigation display unit
    • Faulty rear controller and screen
    • An open or high resistance in the wire
    • Poor ground (G504) or an open in the ground wire
    P16 GRN Transmission range switch in P position Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty transmission range switch
    • An open or high resistance in the wire
    • Poor ground (G101)or an open in the ground wire
    Transmission range switch in any position other than P Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty transmission range switch
    • A short to ground in the wire
    P13 PNK Ignition key inserted into the ignition switch Measure the voltage to ground:
    There should be less than 0.2 V.
    • Faulty ignition key switch
    • Poor ground (G601) or an open in the ground wire
    • An open or high resistance in the wire
    Ignition switch in LOCK (0) position and the ignition key removed from the ignition switch Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty ignition key switch
    • A short to ground in the wire

    Rear Fuse/Relay Box 

  7. Turn the ignition switch to LOCK (0).
  8. Remove the left rear side trim (see TRIM REMOVAL/INSTALLATION - REAR SIDE AREA ).
  9. Disconnect rear fuse/relay box connectors B (34P) and C (42P).
    Fig 2: Identifying Rear Fuse/Relay Box Connectors B (34P)
    G08055253Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 3: Identifying Rear Fuse/Relay Box Connectors C (42P)
    G08055254Courtesy 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, do the following input tests:
    • 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 12.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    C37 ORN Connect battery power to C37 terminal momentarily. Check keyless buzzer operation:
    The keyless buzzer should sound.
    • Faulty keyless buzzer
    • Poor ground (G603) or an open in the ground wire
    • An open or high resistance in the wire
  12. Reconnect the connectors, then turn the ignition switch to ON (II), and do the following input tests:
    • 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 13.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    B4 WHT Under all conditions 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 main under-hood fuse box
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire

    Relay Control Module 

  13. Turn the ignition switch to LOCK (0).
  14. Remove the under-hood fuse/relay box (see DTC B1065: RELAY CONTROL MODULE LOST COMMUNICATION WITH DRIVER'S MPCS UNIT (DRLOCKSW MESSAGE) ).
  15. Disconnect under-hood fuse/relay box (relay control module part) connector D (10P) and H (9P).
    Fig 4: Identifying Disconnect Under-Hood Fuse/Relay Box (Relay Control Module Part) Connector D (10P)
    G08055255Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 5: Identifying Disconnect Under-Hood Fuse/Relay Box (Relay Control Module Part) Connector H (9P)
    G08055256Courtesy of AMERICAN HONDA MOTOR CO., INC.
  16. 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 17.
  17. With the connectors still disconnected, do the following input tests:
    • 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 18.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    H4 LT GRN Connect battery power to H4 terminal Check horn (high) operation: The horn (high) should sound.
    • Faulty horn (high)
    • Poor ground
    • An open or high resistance in the wire
    H5 LT GRN Connect battery power to H5 terminal Check horn (low) operation: The horn (low) should sound.
    • Faulty horn (low)
    • Poor ground
    • An open or high resistance in the wire
  18. Reconnect the connectors, then turn the ignition switch to ON (II), and do the following input tests.
    • 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 19.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    D6 WHT Under all conditions 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 main under-hood fuse box
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the Wire
    H3
    • Blown No. 11 (15 A) fuse in the main under-hood fuse box
    • Faulty main under-hood fuse box
    • An open or high resistance in the wire
    D9 GRN Hood open Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G201) or an open in the ground wire
    • Faulty security hood switch
    • An open or high resistance in the wire
    Hood closed Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty security hood switch
    • A short to ground in the wire

    Driver's MPCS Unit 

  19. Turn the ignition switch to LOCK (0).
  20. Remove the driver's door panel (see FRONT DOOR PANEL REMOVAL/INSTALLATION ).
  21. Disconnect driver's MPCS unit connectors A (40P) and B (14P).
    Fig 6: Identifying Driver's MPCS Unit Connectors A (40P)
    G08055257Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 7: Identifying Driver's MPCS Unit Connectors B (14P)
    G08055258Courtesy of AMERICAN HONDA MOTOR CO., INC.
  22. 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 23.
  23. With the connectors still disconnected, do the following input tests:
    • 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 24.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    A8 GRY Under all conditions Check for continuity between A8 terminal and front passenger's MPCS unit connector A (28P) terminal No. 4:
    There should be continuity.
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire
    Check for continuity to ground:
    There should be no continuity.
    • Faulty under-dash fuse/relay box
    • A short to ground in the wire
    A23.A27 PNK.BRN Driver's door lock switch in LOCK Check for continuity between the terminals:
    There should be continuity.
    • Faulty driver's door lock switch
    • An open or high resistance in the wire
    Driver's door lock switch in neutral or UNLOCK Check for continuity between the terminals:
    There should be no continuity.
    • Faulty driver's door lock switch
    • A short to ground in the wire
    A24.A27 RED.BRN Driver's door lock switch in UNLOCK Check for continuity between the terminals:
    There should be continuity.
    • Faulty driver's door lock switch
    • An open or high resistance in the wire
    Driver's door lock switch in neutral or LOCK Check for continuity between the terminals:
    There should be no continuity.
    • Faulty driver's door lock switch
    • A short to ground in the wire.
    A27.A4 BRN.GRY Connect A7 and A27 terminals, and A4 and A5 terminals with jumper wires Check the driver's door lock switch lights: The switch light should come on.
    • Faulty driver's door lock switch
    • Blown LED
    • An open or high resistance in the wire
  24. Reconnect the connectors, then turn the ignition switch to ON (II), and do the following input tests:
    • 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 25.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    A5 BLK In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • An open or high resistance in the wire
    B14
    A7 WHT Under all conditions 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 main under-hood fuse box
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire
    A27 BRN
    A25 YEL Ignition switch ON (II) 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 ignition switch
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire
    A1 GRN Driver's door lock knob switch in UNLOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • Faulty driver's door lock knob switch
    • An open or high resistance in the wire
    Driver's door lock knob switch in LOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty driver's door lock knob switch
    • A short to ground in the wire
    A2 PUR Driver's door lock knob switch in LOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • Faulty driver's door lock knob switch
    • An open or high resistance in the wire
    Driver's door lock knob switch in UNLOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty driver's door lock knob switch
    • A short to ground in the wire
    A21 BLU Driver's door key cylinder switch in UNLOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • Faulty driver's door key cylinder switch
    • An open or high resistance in the wire
    Driver's door key cylinder switch in neutral or LOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty driver's door key cylinder switch
    • A short to ground in the wire
    A22 LT BLU Driver's door key cylinder switch in LOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • Faulty driver's door key cylinder switch
    • An open or high resistance in the wire
    Driver's door key cylinder switch in neutral or UNLOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty driver's door key cylinder switch
    • A short to ground in the wire
    A6 GRN Left rear door lock knob switch in UNLOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G601) or an open in the ground wire
    • Faulty left rear door lock knob switch
    • An open or high resistance in the wire
    Left rear door lock knob switch in LOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty left rear door lock knob switch
    • A short to ground in the wire

    Front Passenger's MPCS Unit 

  25. Turn the ignition switch to LOCK (0).
  26. Remove the front passenger's door panel (see FRONT DOOR PANEL REMOVAL/INSTALLATION ).
  27. Disconnect front passenger's MPCS unit connectors A (28P) and B (14P).
    Fig 8: Identifying Front Passenger's MPCS Unit Connectors A (28P)
    G08055259Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 9: Identifying Front Passenger's MPCS Unit Connectors B (14P)
    G08055260Courtesy of AMERICAN HONDA MOTOR CO., INC.
  28. 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 29.
  29. With the connectors still disconnected, do the following input tests:
    • 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 30.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    A4 GRY Under all conditions Check for continuity between A4 terminal and driver's MPCS unit connector A (40P) terminal No. 8:
    There should be continuity.
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire
    Check for continuity to ground:
    There should be no continuity.
    • Faulty under-dash fuse/relay box
    • A short to ground in the wire
    A15.A20 PNK.BRN Front passenger's door lock switch in LOCK Check for continuity between the terminals:
    There should be continuity.
    • Faulty front passenger's door lock switch
    • An open or high resistance in the wire
    Front passenger's door lock switch in neutral or UNLOCK Check for continuity between the terminals:
    There should be no continuity.
    • Faulty front passenger's door lock switch
    • A short to ground in the wire
    A16.A20 ORN.BRN Front passenger's door lock switch in UNLOCK Check for continuity between the terminals:
    There should be continuity.
    • Faulty front passenger's door lock switch
    • An open or high resistance in the wire
    Front passenger's door lock switch in neutral or LOCK Check for continuity between the terminals:
    There should be no continuity.
    • Faulty front passenger's door lock switch
    • A short to ground in the wire.
    A20.A1 BRN.GRY Connect A2 and A20 terminals, and A1 and A7 terminals with jumper wires Check the front passenger's door lock switch lights: The switch light should come on.
    • Faulty front passenger's door lock switch
    • Blown LED
    • An open or high resistance in the wire
  30. Reconnect the connectors, then turn the ignition switch to ON (II), and do the following input tests:
    • 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 31.
    Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained
    A7 BLK In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G506) or an open in the ground wire
    • An open or high resistance in the wire
    B14 BLK In all ignition switch positions Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G507) or an open in the ground wire
    • An open or high resistance in the wire
    A2 WHT Under all conditions 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 main under-hood fuse box
    • Faulty under-dash fuse/relay box
    • An open or high resistance in the wire
    A20 BRN
    A17 RED Front passenger's door lock knob switch in UNLOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G506) or an open in the ground wire
    • Faulty front passenger's door lock knob switch
    • An open or high resistance in the wire
    Front passenger's door lock knob switch in LOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty front passenger's door lock knob switch
    • A short to ground in the wire
    A26 PUR Right rear door lock knob switch in UNLOCK Measure the voltage to ground:
    There should be less than 0.2 V.
    • Poor ground (G606) or an open in the ground wire
    • Faulty right rear door lock knob switch
    • An open or high resistance in the wire
    Right rear door lock knob switch in LOCK Measure the voltage to ground:
    There should be at least 5 V.
    • Faulty right rear door lock knob switch
    • A short to ground in the wire
  31. If multiple failures are found on more than one control unit, replace the under-dash fuse/relay box (includes the MICU) (see REMOVAL AND INSTALLATION ). If input failures are related to a particular control unit, replace the control unit.
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