Control Unit Input Test

Multiplex Integrated Control Unit 

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.
   NOTE: All connectors are wire side of female terminals.
   Fig 1: Identifying Multiplex Integrated Control Unit Connector Terminals

   Courtesy 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 are 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.
     WIRE CAVITY REFERENCE CHART
     
     

     Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
     H14	ORN	Under all conditions	Attach to ground: The ignition key light should come on.	Blown No. 7 (10A) fuse in the driver's under-dash 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, 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, go to step 7.
     WIRE CAVITY REFERENCE CHART
     
     

     Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
     E9-H9	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
     P1	BRN			Poor ground (G502) An open in the wire
     Q1	YEL	Ignition switch ON (II), driver's seat belt is buckled.	Measure the voltage to ground: There should be 5 V or more.	Poor ground (G601) Faulty driver's seat belt buckle switch An open in the wire
     		Ignition switch ON (II), driver's seat belt is unbuckled.	Measure the voltage to ground: There should be less than 1 V.	Faulty driver's seat belt buckle switch A short to ground in the wire

   Gauge Control Module 

7. Turn the ignition switch OFF.
8. Remove the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).
9. Disconnect gauge control module connectors A (20P) and B (28P).
   Fig 2: Identifying Gauge Control Module Connectors Terminals

   Courtesy 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. Reconnect the connectors to the gauge control module, 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, go to step 12.
      WIRE CAVITY REFERENCE CHART
      
      

      Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
      A7	BLK	Under all conditions	Measure the voltage to ground: There should be less than 0.5 V.	Poor ground(G501) An open in the wire
      A8	BLK			Poor ground(G501) An open in the wire
      B1	PNK	Ignition switch ON (II)	Measure the voltage to ground: There should be battery voltage.	Blown No. 21 (10 A) fuse in the driver's under-dash fuse/relay box An open in the wire
      B2	WHT	Under all conditions	Measure the voltage to ground: There should be battery voltage.	Blown No. 15 (40 A) fuse in the under-hood fuse/relay box Blown No. 7 (10 A) fuse in the driver's under-dash fuse/relay box An open in the wire
      B27	LT GRN	Ignition switch ON (II)	Measure the voltage to ground: There should be less than 1 V.	Faulty oil pressure switch An open in the wire
      		Engine running	Measure the voltage to ground: There should be 5 V or more.	Faulty oil pressure switch A short to ground in the wire

12. Do the gauge self-diagnostic procedure (see SELF-DIAGNOSTIC FUNCTION ).
    • If the beeper sounds and the seat belt reminder light flashes, go to step 13.
    • If the beeper does not sound or the seat belt reminder light does not flash, replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).
13. Substitute a known-good gauge control module, and recheck the system.
    • If the symptom is gone, the gauge control module is faulty; replace it (see GAUGE CONTROL MODULE REPLACEMENT ).
    • If the symptom is still present, the multiplex integrated control unit (MICU) is faulty; replace the under-dash fuse/relay box (see DRIVER'S UNDER-DASH FUSE/RELAY BOX (MICU) REMOVAL/INSTALLATION ).