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Home >> Acura >> 2012 >> MDX >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Keyless/Power Door Locks/Security System >> Control Unit Input Test

Control Unit Input Test

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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