Multiplex Control Unit Input Test

NOTE: If the multiplex control unit is replaced, never use a multiplex control unit other than the one which is manufactured by the original multiplex control unit maker. Using other multiplex control units, manufactured by a non-original maker could cause a malfunction of communication among the multiplex control unit.

Door Unit:

Remove the driver's door panel, and disconnect the connectors from the door multiplex control unit.
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 3.
Make the following input tests at connector A.
- If a test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 4.
  
  Fig 1: Identifying Door Multiplex Control Unit Connector A Terminals
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
  
  Fig 2: Multiplex Control Unit Input Test Table (Door Unit)
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
  
  Passenger's Unit:
- Remove the passenger's multiplex control unit from the passenger's under-dash fuse/relay box.
- 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 6.
- Make the following input tests at connector B and the fuse/relay box socket.
  - If a test indicates a problem, find and correct the cause, then recheck the system.
  - If all the input tests prove OK, go to step 7.
    
    Fig 3: Identifying Passenger's Multiplex Control Unit Connector B & Passenger's Under-Dash Fuse/Relay Box Socket Terminals
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
    
    Fig 4: Multiplex Control Unit Input Test Table (Passenger's Unit)
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
  Driver's Unit:
- Remove the driver's multiplex control unit from the driver's under-dash fuse/relay box.
- 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 9.
- Make the following input tests at connector B and the fuse/relay box socket.
  - If a test indicates a problem, find and correct the cause, then recheck the system.
  - If all the input tests prove OK, troubleshoot the Multiplex Control System (see Troubleshooting ).
    
    Fig 5: Identifying Driver's Multiplex Control Unit Connector B & Driver's Under-Dash Fuse/Relay Box Socket Terminals
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
    
    Fig 6: Multiplex Control Unit Input Test Table (Driver's Unit)
    Courtesy of AMERICAN HONDA MOTOR CO., INC.