Control Unit Input Test

Multiplex Integrated Control Unit (MICU) 

1. Turn the ignition switch to LOCK (0).
2. Remove the left kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREAS ).
3. Disconnect driver's under-dash fuse/relay box connectors E (16P), F (14P), H (14P), and P(30P) (see DRIVER'S UNDER-DASH FUSE/RELAY BOX ).
   NOTE: All connectors are wire side of female terminals.
   Fig 1: Identifying Driver Under-Dash Fuse/Relay Box Connectors E (16P), F (14P), H (14P) And P (30P)

   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 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 these input tests 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.
   WIRE CAVITY CHART
   
   

   Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired 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 to ON (II) and make these input tests 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.
   WIRE CAVITY 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
   P14	BLK	Under all conditions	Measure the voltage to ground: There should be less than 0.5 V.	Poor ground (G401) An open in the wire
   F14	BLU/RED	Driver's seat belt unbuckled	Measure the voltage to ground: There should be less than 1 V.	Faulty driver's seat belt buckle switch Poor ground (G602) An open in the wire
   		Driver's seat belt buckled	Measure the voltage to ground: There should be 5 V or more.	Faulty driver's seat belt buckle switch A short to ground in the wire
   P2	RED/WHT	Ignition key in the ignition switch	Measure the 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	Measure the voltage to ground: There should be 5 V or more.	Faulty ignition key switch A short to ground in the wire

   Gauge Control Module 

7. Turn the ignition switch to LOCK (0). 
8. Remove the gauge control module (see  GAUGE CONTROL MODULE REPLACEMENT  ). 
9. Disconnect gauge control module connector A (30P). 
   Fig 2: Identifying Gauge Control Module Connector A (30P)

   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. With the connectors still disconnected, make these input tests 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.
    WIRE CAVITY CHART
    
    

    Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
    A28	BLU/YEL	Engine OFF	Check for continuity to ground: There should be continuity.	Faulty 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 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 indicator flashes go to step 14.
    • If the beeper does not sound or the seat belt reminder indicator 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.