Control Unit Input Test: MICU

WARNING: This page is about a different car, the 2011 Honda Pilot, 2010 Honda Pilot, and 2009 Honda Pilot. However, it is still accessible from the selected car via links, so may be relevant.

Turn the ignition switch to LOCK (0), and remove the driver's dashboard lower cover (see INSTRUMENT PANEL REMOVAL/INSTALLATION ).
Disconnect under-dash fuse/relay box connectors E, F, G, K, R and T.
NOTE: All connector views are shown from the wire side of female terminals.

Fig 1: Identifying E (42P), F (34P) & G (21P) Terminal Identification
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 4.

Reconnect the connectors to the under-dash fuse/relay box, and do these input tests at the following 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 5.

TEST CONDITION TABLE

Cavity

Wire

Test condition

Test: Desired result

Possible cause if desired result is not obtained

BLK

In all ignition switch positions

Measure the voltage to ground:
There should be less than 0.2 V.

Poor ground (G401)
An open or high resistance in the in the ground wire

T34

F20

BLK

In all ignition switch positions

Measure the voltage to ground:
There should be less than 0.2 V.

Poor ground (G501)
An open or high resistance in the in the ground wire

PNK

Under all conditions

Measure the voltage to ground:
There should be battery voltage.

Blown No. 23 (10 A) fuse in the under-hood fuse/relay box
Faulty under-hood fuse/relay box
An open or high resistance in the in the wire

WHT

Under all conditions

Measure the voltage to ground:
There should be battery voltage.

Blown No. 22 (10 A) fuse in the under-hood fuse/relay box
Faulty under-hood fuse/relay box
An open or high resistance in the in the wire

RED

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 (G401) 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 more than 5 V.

Faulty ignition key switch
A short to ground in the wire
Faulty MICU

E37

YEL

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 more than 5 V.

Faulty driver's door switch
Faulty under-dash fuse relay box
A short to ground in the wire

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 at least 5 V.

Faulty front passenger's door switch
Faulty under-dash fuse relay box
A short to ground in the wire

E17

LT BLU

Left rear door open

Measure the voltage to ground:
There should be less than 0.2V.

Faulty left rear door switch
Faulty front passenger's 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
Faulty under-dash fuse/relay box
A short to ground in the wire

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
Faulty under-dash fuse/relay box
A short to ground in the wire

E36⁽¹⁾

LT GRN

Tailgate open

Measure the voltage to ground:
There should be less than 0.2 V.

Faulty tailgate latch switch
Poor ground (G601) or an open in the ground wire
An open in the wire

Tailgate closed

Measure the voltage to ground:
There should be at least 5 V.

Faulty tailgate latch switch
A short to ground in the wire

R10

WHT

Under all conditions

Measure the voltage to ground:
There should be battery voltage.

Faulty under-dash fuse/relay box

PNK

Interior light switch in the DOOR position

Connect a jumper wire to ground:
The individual map lights and ignition key light should come on.

Faulty under-dash fuse/relay box
Faulty interior light switch
Faulty map lights
Faulty ignition key switch
Blown bulb(s)
An open or high resistance in the wire

⁽¹⁾	Without power tailgate

Door Multiplex Control Unit

Turn the ignition switch to LOCK (0), and remove the power window master switch (see REAR POWER WINDOW SWITCH TEST/REPLACEMENT ).
Disconnect the 37P connector from the power window master switch.

Fig 2: Identifying Power Window Master Switch 37P Connector Terminal Identification
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 8.

Reconnect the 37P connector to the power window master switch, and do these input tests at the following 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 9.

TEST CONDITION TABLE

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
32	BLK	Under all conditions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G401) An open or high resistance in the wire
37	BLK	Under all conditions		Poor ground (G401) An open or high resistance in the wire
13	WHT	Under all conditions	Measure the voltage to ground: There should be battery voltage.	Blown No. 23 (10 A) fuse in the under-hood fuse/relay box Faulty under-dash fuse/relay box An open in the wire
30	BRN	Driver's door lock knob switch in LOCK	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G401) or open in the ground wire Faulty driver's door lock knob switch An open or high resistance in the wire
30	BRN	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 Faulty power window master switch
31	RED	Driver's door lock knob switch in UNLOCK	Measure the voltage to ground: There should be less than 2.0 V.	Poor ground (G401) or an open in the ground wire. Faulty driver's door lock knob switch An open or high resistance in the wire
31	RED	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 Faulty power window master switch A short to ground in the wire

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.