DLC Circuit Troubleshooting (2016 2017 2018)

DLC Circuit Troubleshooting

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 12.

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.

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 9.

NO

Go to the symptom troubleshooting for 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 ABS indicator or the VSA indicator come on and go off?

YES

The VSA system is OK. Go to step 9.

NO

Go to the symptom troubleshooting for ABS indicator, brake system indicator (red), VSA indicator, and brake system indicator (amber) do not go off .
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 9.

NO

Go to the EPS symptom troubleshooting for EPS indicator does not go off, and no DTCs are stored .
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 symptom troubleshooting information .

NO

The immobilizer system is OK. Go to step 9.
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 9.
Body electrical system check
-1. Do 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 9.

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.

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

NOTE: Before disconnecting the SRS unit connector, do the 12 volt battery terminal disconnection procedure and wait for at least 3 minutes.

K LINE

Immobilizer-keyless control unit 7P connector (without keyless access system)
Audio unit connector A (24P)
Keyless access control unit connector C (20P) (with keyless access system)
Under-dash fuse/relay box connector D (24P)
VSA modulator-control unit 21P connector
Front passenger's weight sensor unit A (6P) (USA and Canada models)

L-LINE

SRS unit connector A (39P) (SRS unt connector A (39P) type)
Keyless access control unit connector C (20P) (with keyless access system)

-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
Immobilizer-keyless control unit 7P connector (without keyless access system)	No. 3
Audio unit connector A (24P) (with audio)	No. 13
Keyless access control unit connector C (20P) (with keyless access system)	No. 4
Under-dash fuse/relay box connector D (24P)	No. 13
VSA modulator-control unit 21P connector	No. 17
Front passenger's weight sensor unit A (6P) (USA and Canada models)	No. 2

L-LINE

Connector	Terminal
SRS unit connector A (39P) (SRS unt connector A (39P) type)	No. 19
Keyless access control unit connector C (20P) (with keyless access system)	No. 6

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

YES

Go to step 10.

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. If the 12 volt battery negative terminal is disconnected in step 9-3, do the 12 volt battery terminal reconnection procedure .

-3. Turn the vehicle to the ON mode.

-4. Measure the voltage between test points 1 and 2.

Test condition

Vehicle ON mode

Test point 1	DLC (16P) No. 7
	DLC (16P) No. 15
Test point 2	Body ground

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

Is there any voltage?

YES

Go to step 1212.

Go to step 11.

Shorted wire check (K LINE line, L-LINE line):
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
- Immobilizer-keyless control unit 7P connector (without keyless access system)
- Audio unit connector A (24P) (with display audio)
- Keyless access control unit connector C (20P) (with keyless access system)
- Under-dash fuse/relay box connector D (24P)
- VSA modulator-control unit 21P connector
- Front passenger's weight sensor unit A (6P) (USA and Canada models)
L-LINE
- SRS unit connector A (39P) (SRS unt connector A (39P) type)
  NOTE: Before disconnecting the SRS unit connector, do the 12 volt battery terminal disconnection procedure and wait for at least 3 minutes.
- Keyless access control unit connector C (20P) (with keyless access system)
Does continuity go away 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 immobilizer-keyless control unit, the audio unit, the keyless access control unit, the under-dash fuse/relay box (MICU), the VSA modulator-control unit, the front passenger's weight sensor unit, or the DLC (16P) No. 15 (L-LINE) and the SRS unit, the keyless access control unit.
Body electrical system (B-CAN) check
-1. Do the gauge self-diagnostic function .

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

Is DTC U0029 and/or U0100 indicated?

YES

Do the PCM power and ground circuit troubleshooting .

NO

Go to step 13.

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 14.

Repair an open in the +B BACK UP wire between DLC (16P) No. 16 and the No. B21 (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 15.

Repair an open in the GND wire between DLC (16P) No. 4 and G403.

Open wire check (F-CAN_H line)

-1. Jump the SCS line with the HDS.

-2. Disconnect the following connector.

PCM connector A (51P)

-3. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	PCM connector A (51P): disconnected
Test point 1	PCM connector A (51P) No. 3
Test point 2	DLC (16P) No. 6

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

Is there continuity?

YES

The F-CAN_H line wire is not open. Go to step 16.

Repair an open in the F-CAN_H wire between the PCM (A3) and the DLC (16P).

Open wire check (F-CAN_L line)

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	PCM connector A (51P): disconnected
Test point 1	PCM connector A (51P) No. 4
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 , 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 .

Repair an open in the F-CAN_L wire between the PCM (A4) and the DLC (16P).