Control Unit Input Test

Before testing, troubleshoot the multiplex control system (see TROUBLESHOOTING ).
Remove the driver's dashboard lower cover (see DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTAL ).
Disconnect the under-dash fuse/relay box connectors.
NOTE: All connectors are wire side of female terminals.

Fig 1: Identifying Control Unit Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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.

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 all the input tests prove OK, go to step 6.

INPUT TEST (CONNECTORS DISCONNECTED)

Cavity	Wire	Test condition	Test: Desired result	Possible cause if result is not obtained
K2	BLU/ORN	Under all conditions	Check for continuity between the K2 terminal and the keyless receiver unit 5P connector No. 2 terminal: There should be continuity, end to end with no continuity to ground.	An open in the wire Short to ground
X8	WHT/BLK	Under all conditions	Attach to ground: Ignition key light should come on.	Blown No. 3 (15 A) fuse in the under-hood fuse/relay box Faulty ignition key light (LED) An open in the wire

Reconnect the connectors to the under-dash fuse/relay box and turn the ignition switch ON (II) to keep the system awake, then make these input tests at the appropriate connectors on the 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, the multiplex control unit must be faulty, replace the under-dash fuse/relay box assembly.

INPUT TEST (CONNECTORS CONNECTED)

Cavity	Wire	Test condition	Test: Desired result	Possible cause if result is not obtained
P18	RED	Tailgate open	Check for voltage to ground: There should be less than 1 V.	Faulty tailgate switch An open in the wire
P18	RED	Tailgate closed	Check for voltage to ground: There should be 5 V or more.	Faulty tailgate switch Short to ground
Q3	GRN	Driver's door open	Check for voltage to ground: There should be less than 1 V.	Faulty driver's door switch An open in the wire
Q3	GRN	Driver's door closed	Check for voltage to ground: There should be 5 V or more.	Faulty driver's door switch Short to ground
Q4	LT GRN/RED	Front passenger's door open	Check for voltage to ground: There should be less than 1 V.	Faulty front passenger's door switch An open in the wire
		Front passenger's door closed	Check for voltage to ground: There should be 5 V or more.	Faulty front passenger's door switch Short to ground
		Left (right) rear door open	Check for voltage to ground: There should be less than 1 V.	Faulty left (right) rear door switch An open in the wire
		Left (right) rear door closed	Check for voltage to ground: There should be 5 V or more.	Faulty left (right) rear door switch Short to ground
X5	RED/WHT	Ignition key inserted into the ignition switch	Check for voltage to ground: There should be less than 1 V.	Poor ground (G401) Faulty ignition key switch An open in the wire
X5	RED/WHT	Ignition key removed from the ignition switch	Check for voltage to ground: There should be 5 V or more.	Faulty ignition key switch Short to ground
Y8	YEL/RED	Driver's door lock knob switch locked	Check for voltage to ground: There should be less than 1 V.	Poor ground (G501) Faulty driver's door lock knob switch An open in the wire
Y8	YEL/RED	Driver's door lock knob switch unlocked	Check for voltage to ground: There should be 5 V or more.	Faulty driver's door lock knob switch Short to ground
O7	GRN/RED	Ceiling light switch in middle position, all doors closed	Attach to ground: Ceiling light(s) should come on.	Blown No. 3 (15 A) fuse in the under-hood fuse/relay box Blown bulb Faulty ceiling light An open in the wire