Control Unit Input Test

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before testing the entry lights control system, troubleshoot the multiplex integrated control unit first, using B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Under-dash Fuse/Relay Box

Turn the ignition switch to LOCK (0) and remove the left kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREAS ).
Disconnect under-dash fuse/relay box connectors E, F, H, P, Q, and W.
NOTE: All connector views are wire side of female terminals.

Fig 1: Identifying Under-Dash Fuse/Relay Box Connector E (16P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 2: Identifying Under-Dash Fuse/Relay Box Connector P (30P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 3: Identifying Under-Dash Fuse/Relay Box Connector F (14P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 4: Identifying Under-Dash Fuse/Relay Box Connector Q (14P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 5: Identifying Under-Dash Fuse/Relay Box Connector H (14P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 6: Identifying Under-Dash Fuse/Relay Box Connector W (5P) 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 4.

Reconnect the connectors, turn the ignition switch to ON (II), and do the following input tests:

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.

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
E9	BLK	In all ignition switch positions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G601) or an open in the ground wire An open or high resistance in the wire
H9
Q4
P1	BRN	In all ignition switch positions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G502) or an open in the ground wire An open or high resistance in the wire
P13	PNK	Ignition key inserted into the ignition switch	Measure the voltage to ground: There should be less than 0.2 V.	Faulty ignition key switch Faulty under-dash fuse/relay box Poor ground (G601) or an open in the ground wire An open or high resistance in the wire
P13	PNK	Ignition switch LOCK (0) and the ignition key removed from the ignition switch	Measure the voltage to ground: There should be at least 5 V.	Faulty ignition key switch A short to ground in the wire
E15	GRN	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
E15	GRN	Driver's door closed	Measure the voltage to ground: There should be at least 5 V.	Faulty driver's door switch A short to ground in the wire
H12	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
H12	LT GRN	Front passenger's door closed	Measure the voltage to ground: There should be at least 5 V.	Faulty front passenger's door switch A short to ground in the wire
Q2	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
Q2	GRY	Right rear door closed	Measure the voltage to ground: There should be at least 5 V.	Faulty right rear door switch A short to ground in the wire
Q8	GRN	Left rear door open	Measure the voltage to ground: There should be less than 0.2 V.	Faulty left rear door switch Faulty left rear door switch ground An open or high resistance in the wire
Q8	GRN	Left rear door closed	Measure the voltage to ground: There should be at least 5 V.	Faulty left rear door switch A short to ground in the wire
F14	ORN	Under all conditions	Attach to ground: The ignition key light should come on.	Blown No. 4 (40 A) fuse in the main under-hood fuse box Blown No. 6 (7.5 A) fuse in the under-dash fuse/relay box Faulty main under-hood fuse box Faulty under-dash fuse/relay box Faulty ignition key light An open or high resistance in the wire
W4	LT GRN	Under all conditions (Interior light control button (DOOR) pressed)	Attach to ground: The individual map lights and footwell lights should come on.	Blown No. 4 (40 A) fuse in the main under-hood fuse box Blown No. 6 (7.5 A) fuse in the under-dash fuse/relay box Faulty main under-hood fuse box Faulty under-dash fuse/relay box Faulty roof console Faulty rear individual map lights Blown footwell light bulbs An open or high resistance in the wire

Rear Fuse/Relay Box

Turn the ignition switch to LOCK (0).
Remove the left rear side trim (see TRIM REMOVAL/INSTALLATION - REAR SIDE AREA ).
Disconnect rear fuse/relay box connector B (34P).

Fig 7: Identifying Rear Fuse/Relay Box Connector B (34P)
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 9.

Reconnect the connectors, then turn the ignition switch to ON (II), and do the following input tests:

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 10.

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
B18	BLK	In all ignition switch positions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G603, G604) or an open in the ground wire An open or high resistance in the wire
B29	BLK	In all ignition switch positions
B4	WHT	Under all conditions	Measure the voltage to ground: There should be battery voltage.	Blown No. 4 (40 A) fuse in the main under-hood fuse box Faulty main under-hood fuse box Blown No. 7 (10 A) fuse in the under-dash fuse/relay box Faulty under-dash fuse/relay box An open or high resistance in the wire
B23	LT BLU	Ignition switch ON (II)	Measure the voltage to ground: There should be battery voltage.	Blown No. 21 (7.5 A) fuse in the under-dash fuse/relay box Faulty under-dash fuse/relay box An open or high resistance in the wire

Driver's MPCS Unit

Turn the ignition switch to LOCK (0).
Remove the driver's door panel (see FRONT DOOR PANEL REMOVAL/INSTALLATION ).
Disconnect driver's MPCS unit connectors A (40P) and B (14P).

Fig 8: Identifying Driver's MPCS Unit Connectors A (40P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 9: Identifying Driver's MPCS Unit Connectors B (14P) 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 14.

With the connectors still disconnected, do the following input tests:

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 15.

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
A23.A27	PNK.BRN	Driver's door lock switch in LOCK	Check for continuity: There should be continuity.	Faulty driver's door lock switch An open or high resistance in the wire
A23.A27	PNK.BRN	Driver's door lock switch in neutral or UNLOCK	Check for continuity: There should be no continuity.	Faulty driver's door lock switch A short to ground in the wire
A24.A27	RED.BRN	Driver's door lock switch in UNLOCK	Check for continuity: There should be continuity.	Faulty driver's door lock switch An open in the wire
A24.A27	RED.BRN	Driver's door lock switch in neutral or LOCK	Check for continuity: There should be no continuity.	Faulty driver's door lock switch A short to ground in the wire

Reconnect the connectors, and do the following input tests:

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 16.

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
A5	BLK	In all ignition switch positions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground(G601) or an open in the ground wire An open or high resistance in the wire
B14	BLK	In all ignition switch positions
A7	WHT	Under all conditions	Measure the voltage to ground: There should be battery voltage.	Blown No. 4 (40 A) fuse in the main under-hood fuse box Faulty main under-hood fuse box Blown No. 7 (10 A) fuse in the under-dash fuse/relay box Faulty under-dash fuse/relay box An open or high resistance in the wire
A25	YEL	Ignition switch ON (II)	Measure the voltage to ground: There should be battery voltage.	Blown No. 21 (7.5 A) fuse in the under-dash fuse/relay box Faulty under-dash fuse/relay box An open or high resistance 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.