DLC CIRCUIT TROUBLESHOOTING (2019 2020 2021: With CAN GATEWAY)

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. How to Connect the HDS

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 14.

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

DTC (PGM-FI)

Are any Pending or Confirmed DTCs indicated?

YES

Go to the indicated DTC's troubleshooting.

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

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

If the HDS does not communicate with the VSA system, go to step 6.

If the HDS does not communicate with the EPS system, go to step 7.

If the HDS does not communicate with the ONE-PUSH START system, go to step 8.

If the HDS does not communicate with the BODY ELECTRICAL system, go to step 9.

If the HDS does not communicate with the DRIVING SUPPORT system, go to step 10.

Open wire check (F-CAN A_H line)

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

- 2. Jump the SCS line with the HDS, and wait more than 1 minute.

- 3. Disconnect the following connectors.

CAN gateway 16P connector

PCM connector A (51P) (6-Speed A/T)

PCM connector A (50P) (9-Speed A/T)

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 16P connector: disconnected
	PCM connector A (51P) (6-Speed A/T): disconnected
	PCM connector A (50P) (9-Speed A/T): disconnected

6-Speed A/T

Test point 1	CAN gateway 16P connector (female terminals) No. 3: (1)
Test point 2	PCM connector A (51P) No. 9 - Go to: PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020) .

9-Speed A/T

Test point 1	CAN gateway 16P connector (female terminals) No. 3: (1)
Test point 2	PCM connector A (50P) No. 11 - Go to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .

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Is there continuity?

YES

The F-CAN A_H wire is OK. Go to step 4.

Repair an open in the F-CAN A_H wire between the PCM (A9 or A11) and the CAN gateway.

Open wire check (F-CAN A_L line)

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 16P connector: disconnected
	PCM connector A (51P) (6-Speed A/T): disconnected
	PCM connector A (50P) (9-Speed A/T): disconnected

6-Speed A/T

Test point 1	CAN gateway 16P connector (female terminals) No. 11: (1)
Test point 2	PCM connector A (51P) No. 10 - Go to: PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020) .

9-Speed A/T

Test point 1	CAN gateway 16P connector (female terminals) No. 11: (1)
Test point 2	PCM connector A (50P) No. 10 - Go to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .

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

Is there continuity?

YES

The F-CAN A_L, wire is OK. Check for poor connections or loose terminals at the CAN gateway and the PCM. Go to the PCM Power and Ground Circuit Troubleshooting (9-Speed A/T) (2019 2020 2021) .

Repair an open in the F-CAN A_L wire between the PCM (A10) and the CAN gateway.

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 11.

NO

Go to the SRS Symptom Troubleshooting - SRS indicator stays on, but no DTCs are stored, or cannot be read (2017 2018 2019 2020 2021) .
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 11.

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:

VSA System Symptom Troubleshooting - ABS indicator, brake system indicator (RED), VSA indicator, and brake system indicator (AMBER) do not go OFF (With Auto Idle Stop System) (2019 2020 2021) or

VSA System Symptom Troubleshooting - ABS indicator, brake system indicator (RED), VSA indicator, and brake system indicator (AMBER) do not go OFF (Without Auto Idle Stop System) (2019 2020 2021) .
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 11.

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 (With Auto Idle Stop System) (2019 2020 2021)

EPS indicator does not go OFF (Without Auto Idle Stop System) (2019 2020 2021)
Keyless access system check
-1. Turn the vehicle to the OFF (LOCK) mode.

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

Does the security indicator stay on or blinkΩ

YES

Go to the Keyless Access System Symptom Troubleshooting Information (2019 2020 2021) .

NO

The keyless access system is OK. Go to step 11.
Body electrical system check
-1. Do the Gauges Control Module Self-Diagnostic Function (2019 2020 2021) .

- 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 11.
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, the CMBS indicator, the RDM indicator, the LKAS indicator, and the BSI indicator.

Does the ACC indicator, the CMBS indicator, the RDM indicator, the LKAS indicator, and/or the BSI indicator come on and go off?

YES

The driving support system is OK. Go to step 11.

NO

Go to the driving support system symptom troubleshooting;

ACC - How to Troubleshoot the Adaptive Cruise Control (ACC) (2019 2020 2021) .

CMBS - How to Troubleshoot the Collision Mitigation Braking System (CMBS) (2019 2020 2021) .

RDM - How to Troubleshoot the Road Departure Mitigation (2019 2020 2021) .

LKAS - How to Troubleshoot the Lane Keeping Assist System (LKAS) (2019 2020 2021) .

BSI - How to Troubleshoot the Blind Spot Information System/Cross Traffic Monitor (2019 2020 2021) .

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.

NOTE: Before disconnecting the SRS unit connector, do the 12 Volt Battery Terminal Disconnection procedure and wait for at least 3 minutes.

K-LINE

VSA modulator-control unit 38P connector
Infotainment control unit connector A (20P) (display audio type (8-inch screen))
Audio unit connector A (24P) (color audio type (5-inch screen))
ANC/active sound control unit 20P connector
Keyless access/TPMS control unit C (20P)
Under-dash fuse/relay box connector R (16P)

L-LINE

Keyless access/TPMS control unit C (20P)
SRS unit connector A (39P)

- 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 - Go to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2019 2020 2021)	No. 33
Infotainment control unit connector A (20P)Infotainment Control Unit Connector for Inputs and Outputs (2019 2020 2021) [display audio type (8-inch screen)].	No. 20
Audio unit connector A (24P) - Go to: Audio Unit Connector for Inputs and Outputs (2019 2020 2021) [color audio type (5-inch screen)].	No. 13
ANC/active sound control unit 20P connector - Go to: ANC/Active Sound Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	No. 14
Keyless access/TPMS control unit C (20P) - Go to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	No. 4
Under-dash fuse/relay box connector R (16P) - Go to: MICU Input Test (2019 2020 2021) .	No. 9

L-LINE

Connector	Terminal
Keyless access/TPMS control unit C (20P) - Go to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	No. 6
SRS unit connector A (39P) - Go to: SRS Unit Connector for Inputs and Outputs (2019 2020 2021)	No. 33

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

YES

Go to step 12.

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 11-3, 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) (female terminals) No. 7 and No. 15: (1)
Test point 2	Body ground

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Is there any voltage?

YES

Go to step 14.

Go to step 13.

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
- Infotainment control unit connector A (20P) (display audio type (8-inch screen))
- Audio unit connector A (24P) (color audio type (5-inch screen))
- ANC/active sound control unit 20P connector
- Keyless access/TPMS control unit C (20P)
- Under-dash fuse/relay box connector R (16P)
L-LINE
- Keyless access/TPMS control unit C (20P)
- SRS unit connector A (39P)
  NOTE: Before disconnecting the SRS unit connector, do the 12 Volt Battery Terminal Disconnection procedure and wait for at least 3 minutes.
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 the DLC (16P) No. 7 (K-LINE) and the VSA modulator-control unit, the infotainment control unit, the audio unit, the ANC/active sound control unit, the keyless access/TPMS control unit, the under-dash fuse/relay box, or the DLC (16P) No. 15 (L-LINE) and the keyless access/TPMS control unit, the SRS unit.
Body electrical system (B-CAN) check
-1. Do the Gauges Control Module Self-Diagnostic Function (2019 2020 2021) .

- 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 - Refer to:

PCM Power and Ground Circuit Troubleshooting (6-Speed A/T), ('16-'18 9-Speed A/T) or

PCM Power and Ground Circuit Troubleshooting (9-Speed A/T) (2019 2020 2021) .

NO

Go to step 15.

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) (female terminals) No. 16: (1)
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 16.

Repair an open in the +B BACK UP wire between DLC (16P) No. 16 and the No. A26 fuse. - Refer to: or.

Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

Open wire check (PGND line)

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

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

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Is there battery voltage?

YES

The PGND wire is OK. Go to step 17.

Repair an open in the PGND wire between DLC (16P) No. 4 and G402.

Open wire check (IG1 OPTION line)

-1. Disconnect the following connector.

CAN gateway 16P connector

- 2. Turn the vehicle to the ON mode.

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

Test condition	Vehicle ON mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 9: (1)
Test point 2	Body ground

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

Is there battery voltage?

YES

The IG1 OPTION wire is OK. Go to step 18.

Repair an open in the IG1 OPTION wire between the CAN gateway and the No. C28 fuse - Refer to:

Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

Open wire check (GND line)

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

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 12: (1)
Test point 2	Body ground

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Is there continuity?

YES

The GND wire is OK. Go to step 19.

Repair an open in the GND wire between the CAN gateway and G405.

Open wire check (DIAG-CAN_H line)

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 16P connector: disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 2: (1)
Test point 2	DLC (16P) (female terminals) No. 6: (2)

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

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

Is there continuity?

YES

The DIAG-CAN_H wire is not open. Go to step 20.

Repair an open in the DIAG-CAN_H wire between the CAN gateway and the DLC (16P) No. 6.

Open wire check (DIAG-CAN_L line)

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 10: (1)
Test point 2	DLC (16P) (female terminals) No. 14: (1)

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

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

Is there continuity?

YES

The DIAG-CAN_L wire is not open. Go to step 21.

Repair an open in the DIAG-CAN_L wire between the CAN gateway and the DLC (16P) No. 14.

Shorted wire check (DIAG-CAN_H line)

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	DLC (16P) (female terminals) No. 6: (1)
Test point 2	Body ground

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

Is there continuity?

YES

Repair a short in the DIAG-CAN_H wire between the CAN gateway and the DLC (16P) No. 6.

The DIAG-CAN_H wire is not shorted to ground. Go to step 22.

Shorted wire check (DIAG-CAN_L line)

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	DLC (16P) (female terminals) No. 14: (1)
Test point 2	Body ground

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

Is there continuity?

YES

Repair a short in the DIAG-CAN_L wire between the CAN gateway and the DLC (16P) No. 14.

The DIAG-CAN_L wire is not shorted to ground. Go to step 23.

Shorted wire check (DIAG-CAN_H line to DIAG-CAN_L line)

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

Test condition	Vehicle OFF (LOCK) mode
Test condition	CAN gateway 16P connector: disconnected
Test point 1	DLC (16P) (female terminals) No. 6: (1)
Test point 2	DLC (16P) (female terminals) No. 14: (1)

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

Is there continuity?

YES

Repair a short in the DIAG-CAN_H wire to the DIAG-CAN_L wire between DLC (16P) No. 6 and No. 14.

The DIAG-CAN_H wire and the DIAG-CAN_L wire are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good CAN Gateway - Removal and Installation (2019 2020 2021) , then recheck. If the HDS identifies the vehicle and the CAN gateway was substituted, replace the original CAN Gateway - Removal and Installation (2019 2020 2021) .