DLC Circuit Troubleshooting (L4) (2015-17)

NOTE: If you suspect the HDS or the HDS DLC cable may be the source of the communication problem, verify that they are working properly by connecting them to a known-good, similar vehicle and system, and checking for communication problems.

HDS communication check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Connect the HDS to the DLC.

NOTE: Make sure the HDS is properly connected to the DLC.

- 3. Turn the vehicle to the ON mode, and turn on the HDS.

Does the HDS identify the vehicle?

YES

Go to step 2.

NO

Go to step 13.

Determine possible failure area (PGM-FI system, other systems)

- 1. Check for Pending or Confirmed DTCs in the PGM-FI system with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame

Are any Pending or Confirmed DTCs indicated?

YES

Go to the indicated DTC's troubleshooting.

If the HDS does not communicate with the SRS, go to step 3.

If the HDS does not communicate with the VSA system, go to step 4.

If the HDS does not communicate with the EPS system, go to step 5.

If the HDS does not communicate with the IMMOBI (immobilizer) system, go to step 6.

If the HDS does not communicate with the ONE PUSH START system, go to step 7.

If the HDS does not communicate with the BODY ELECTRICAL system, go to step 8.

If the HDS does not communicate with the DRIVING SUPPORT system, go to step 9.

SRS check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode, and watch the SRS indicator.

Does the SRS indicator come on and go off?

YES

The SRS is OK. Go to step 10.

NO

Go to the symptom troubleshooting for SRS indicator stays on, but no DTCs are stored, or cannot be read - Refer to: SRS indicator stays on, but no DTCs are stored, or cannot be read .
VSA system check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode, and watch the VSA indicator.

Does the VSA indicator come on and go off?

YES

The VSA system is OK. Go to step 10.

NO

Go to the symptom troubleshooting for ABS indicator, brake system indicator (red), VSA indicator, and brake system indicator (amber) do not go off - Refer to: ABS/brake system indicator (red), VSA indicator, and brake system indicator (amber) do not go off (With ACC) or ABS/brake system indicator (red), VSA indicator, and brake system indicator (amber) do not go off (Without ACC) .
EPS system check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Start the engine, and watch the EPS indicator.

Does the EPS indicator come on and go off?

YES

The EPS system is OK. Go to step 10.

NO

Go to the EPS symptom troubleshooting for EPS indicator does not go off, and no DTCs are stored - Refer to: EPS indicator does not go off, and no DTCs are stored (With ACC) or EPS indicator does not go off, and no DTCs are stored (Without ACC) .
Immobilizer system check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode, and watch the immobilizer indicator.

Does the immobilizer indicator stay on or flash?

YES

Go to the immobilizer system troubleshooting .

NO

The immobilizer system is OK. Go to step 10.
Keyless access system check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode, and watch the keyless access indicator and the immobilizer indicator.

Does the keyless access indicator stay on or the immobilizer indicator stay on or flash?

YES

Go to the keyless access system symptom troubleshooting information .

NO

The keyless access system is OK. Go to step 10.
Body electrical system check
- 1. Perform the gauge self-diagnostic function.

- 2. Check the gauge display.

Is Error 2 indicated?

YES

Go to the indicated DTC's troubleshooting.

NO

The body electrical system is OK. Go to step 10.
Driving support system check
- 1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode, and watch the ACC indicator and/or the LKAS indicator.

Does the LKAS indicator, the LDW indicator, and/or the FCW indicator come on and go off?

YES

The driving support system is OK. Go to step 10.

NO

Go to the driving support general troubleshooting information .

Open wire check (K LINE line or L LINE line)

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

- 2. Disconnect the HDS from the DLC.

- 3. Disconnect the control unit (s) on the K LINE or L LINE that does not communicate.

K LINE

VSA modulator-control unit 38P connector
ANC/active sound control unit 20P connector
EPS control unit connector A (11P)
Audio unit connector A (24P) (without navigation)
Audio-navigation unit connector A (24P) (with navigation)
Keyless access/TPMS control unit connector C (20P)
Front passenger's weight sensor unit A (6P)
Under-dash fuse/relay box connector R (16P)

L LINE

Keyless access/TPMS control unit connector C (20P)

- 4. Check for continuity between DLC (16P) No. 7 (K LINE line) and these connector terminals, or DLC (16P) No. 15 (L LINE line) and these connector terminals:

K LINE

Connector	Terminal
VSA modulator-control unit 38P connector	No. 11
ANC/active sound control unit 20P connector	No. 14
EPS control unit connector A (11P)	No. 7
Audio unit connector A (24P) (without navigation)	No. 13
Audio-navigation unit connector A (24P) (with navigation)	No. 13
Keyless access/TPMS control unit connector C (20P)	No. 4
Front passenger's weight sensor unit A (6P)	No. 2
Under-dash fuse/relay box connector R (16P)	No. 12

L LINE

Connector	Terminal
Keyless access/TPMS control unit connector C (20P)	No. 6

Is there continuity between the DLC and the terminals in the chart?

YES

Go to step 11.

Repair an open in the wire between the DLC (K LINE wire or L LINE wire) and the appropriate connector.

Determine possible failure area (short in K LINE line or L LINE line, others)

- 1. Reconnect all connectors.

- 2. Turn the vehicle to the ON mode.

- 3. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
Test point 1	DLC (16P) No. 7 and No. 15
Test point 2	Body ground

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

Is there any voltage?

YES

Go to step 13.

Go to step 12.

Shorted wire check (K LINE line, L LINE line)
- 1. Continue to measure the voltage between DLC (16P) No. 7 (K LINE line) and body ground, or DLC (16P) No. 15 (L LINE line) and body ground while disconnecting these parts, one at a time:

NOTE: Turn the vehicle to the OFF (LOCK) mode before disconnecting the connector, and turn the vehicle to the ON mode before measuring the voltage.

K LINE
- VSA modulator-control unit 38P connector
- ANC/active sound control unit 20P connector
- EPS control unit connector A (11P)
- Audio unit connector A (24P) (without navigation)
- Audio-navigation unit connector A (24P) (with navigation)
- Keyless access/TPMS control unit connector C (20P)
- Front passenger's weight sensor unit A (6P)
- Under-dash fuse/relay box connector R (16P)
L LINE
- Keyless access/TPMS control unit connector C (20P)
Does voltage come back when one of the above components is disconnected?

YES

Replace the part that any voltage was detected when it was disconnected.

NO

Repair a short in the wire between DLC (16P) No. 7 (K LINE) and the VSA modulator-control unit, the ANC/active sound control unit, the EPS control unit, the audio unit, the audio-navigation unit, the keyless access/TPMS control unit, the front passenger's weight sensor unit, the under-dash fuse/relay box (MICU), or DLC (16P) No. 15 (L LINE) and the keyless access/TPMS control unit.
Body electrical system (B-CAN) check
- 1. Perform the gauge self-diagnostic function.

- 2. Check for gauge control module DTCs without the HDS.

Is DTC U0029 and/or U0100 indicated?

YES

Perform the PCM power and ground circuit troubleshooting - Refer to: PCM Power and Ground Circuit Troubleshooting (L4) .

NO

Go to step 14.

Open wire check (+B BACK UP line)

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

- 2. Disconnect the HDS from the DLC.

- 3. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test point 1	DLC (16P) No. 16
Test point 2	Body ground

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

Is there battery voltage?

YES

The +B BACK UP wire is OK. Go to step 15.

Repair an open in the +B BACK UP wire between DLC (16P) No. 16 and the No. A29 (10 A) fuse in the under-hood fuse/relay box.

Open wire check (GND line)

- 1. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test point 1	DLC (16P) No. 4
Test point 2	DLC (16P) No. 16

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

Is there battery voltage?

YES

The GND wire is OK. Go to step 16.

Repair an open in the GND wire between DLC (16P) No. 4 and G306.

Open wire check (F-CAN_H line)

- 1. Disconnect the following connector.

PCM connector A (51P)

- 2. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (51P): disconnected
Test point 1	PCM connector A (51P) No. 2 - Refer to: PCM Connector for Inputs and Outputs (L4)
Test point 2	DLC (16P) No. 6

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

Is there continuity?

YES

The F-CAN_H wire is not open. Go to step 17.

Repair an open in the F-CAN_H wire between the PCM (A2) and DLC (16P) No. 6.

Open wire check (F-CAN_L line)

- 1. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (51P): disconnected
Test point 1	PCM connector A (51P) No. 3 - Refer to: PCM Connector for Inputs and Outputs (L4)
Test point 2	DLC (16P) No. 14

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

Is there continuity?

YES

The F-CAN_L wire is not open. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (Without SH-AWD) , then recheck. If the HDS identifies the vehicle and the PCM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (Without SH-AWD) .

Repair an open in the F-CAN_L wire between the PCM (A3) and DLC (16P) No. 14.