Headlight Leveling Control Unit Input Test (2017 2018 2019 2020)

NOTE:

Before testing, check for DTCs. If any DTCs are indicated, troubleshoot those DTCs first, and combination light switch circuit is OK.
If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to:
Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020)
Before testing, make sure the No. D22 (15 A) fuse in the driver's under-dash fuse/relay box is OK.
Before testing, make sure the No. E21 (7.5 A) fuse in the passenger's under-dash fuse/relay box is OK.

1. Turn the vehicle to the OFF (LOCK) mode.

2. Disconnect the headlight leveling control unit 16P connector.

Headlight leveling control unit 16P connector (female terminals)

Courtesy of HONDA, U.S.A., INC.

3. 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 are OK, go to step 4.

4. With the connector 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 5.

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
11	TAN	Under all conditions	Check for continuity between terminal No. 11 and data link connector (DLC) terminal No. 11:There should be continuity.	An open in the SCS wire

5. Reconnect the connector, 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, replace the headlight leveling control unit .
NOTE: After replacing the headlight leveling control unit, do the headlight initial position learning procedure .

Cavity	Wire	Test condition	Test: Desired result	Possible cause if desired result is not obtained
8	GRY	Vehicle ON mode	Measure the voltage to ground: There should be battery voltage.	Blown No. D22 (15 A) fuse in the driver's under-dash fuse/relay box Blown No. E21 (7.5 A) fuse in the passenger's under-dash fuse/relay box An open or high resistance in the wire
16	BLK	In all power modes	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G402) An open or high resistance in the ground wire
5	PUR	Under all conditions	Check for continuity to ground: There should be continuity.	Poor ground (G402) An open or high resistance in the ground wire
6	YEL	Under all conditions	Check for continuity to ground: There should be continuity.	Poor ground (G402) An open or high resistance in the ground wire
7	GRN	Vehicle ON mode, and headlight switch ON	Measure the voltage between terminals No. 7 and No. 6:There should be about 5 V.	Faulty headlight leveling motor An open or high resistance in the wire
6	YEL	Vehicle ON mode, and headlight switch ON
14	BRN	Vehicle ON mode, and headlight switch ON	Measure the voltage between the terminals No. 14 and No. 6:There should be about 0.5 to 4.5 V.	Faulty headlight leveling motor An open or high resistance in the wire
6	YEL	Vehicle ON mode, and headlight switch ON
3	LT GRN	Vehicle ON mode, and headlight switch ON	Measure the voltage between terminals No. 5 and No. 12:There should be about 5 V. Measure the voltage between terminals No. 3 and No. 5:There should be about 0.5 to 4.5 V.	Faulty front suspension stroke sensor An open or high resistance in the wire
5	PUR
12	PNK
2	WHT	Vehicle ON mode, and headlight switch ON	Measure the voltage between terminals No. 5 and No. 12:There should be about 5 V. Measure the voltage between terminals No. 2 and No. 5:There should be about 0.5 to 4.5 V.	Faulty rear suspension stroke sensor An open or high resistance in the wire
5	PUR
12	PNK