DLC CIRCUIT TROUBLESHOOTING (2019 2020 2021: Without 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 11.

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 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 ONE PUSH START system, go to step 6.

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

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 8.

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 8.

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)

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 8.

NO

Go to the symptom troubleshooting for EPS indicator does not go off - Refer to:

EPS Symptom Troubleshooting - EPS indicator does not go off (With Auto Idle Stop System) (2019 2020 2021)

EPS Symptom Troubleshooting - 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 - Go to: Keyless Access System Symptom Troubleshooting Information (2019 2020 2021) .

NO

The keyless access system is OK. Go to step 8.
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 8.

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)
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 and these connector terminals (K-LINE line), or DLC (16P) No. 15 and these connector terminals (L-LINE line):

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) - Go to:Infotainment Control Unit Connector for Inputs and Outputs (2019 2020 2021)	No. 20
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 9.

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 8-3, 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

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

Is there any voltage?

YES

Go to step 11.

Go to step 10.

Shorted wire check (K-LINE line, L-LINE line)
-1. Continue to measure the voltage between DLC (16P) No. 7 and body ground (K-LINE line), or DLC (16P) No. 15 and body ground (L-LINE line) 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)
- 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 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

Go to the PCM Power and Ground Circuit Troubleshooting (2019 2020 2021) .

NO

Go to step 12.

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 13.

Repair an open in the +B BACKUP wire between DLC (16P) No. 16 and the No. B18 - Refer to: or fuse.

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)

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

Is there battery voltage?

YES

The PGND wire is OK. Go to step 14.

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

Open wire check (F-CAN_H line or F-CAN A_H line)

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

SCS Short

- 2. Disconnect the following connector.

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

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

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

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

6-Speed A/T (F-CAN_H line)

Test point 1	DLC (16P) (female terminals) No. 6: (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 (F-CAN A_H line)

Test point 1	DLC (16P) (female terminals) No. 6: (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) .

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

Is there continuity?

YES

The F-CAN_H, F-CAN A_H wires are not open. Go to step 15.

Repair an open in the F-CAN_H or F-CAN A_H wire between the PCM (A9 or A11) and DLC (16P) No. 6.

Open wire check (F-CAN_L line or F-CAN A_L line)

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

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

6-Speed A/T (F-CAN_H line)

Test point 1	DLC (16P) (female terminals) No. 14: (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 (F-CAN A_H line)

Test point 1	DLC (16P) (female terminals) No. 14: (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_L, F-CAN A_L wires are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to:

PCM (6-Speed A/T), ('16-'18 9-Speed A/T) or

PCM (9-Speed A/T) Removal and Installation (2019 2020 2021) then recheck.

If the HDS identifies the vehicle and the PCM was substituted, replace the original PCM - Refer to:

PCM (6-Speed A/T), ('16-'18 9-Speed A/T)

PCM (9-Speed A/T) Removal and Installation (2019 2020 2021)

Repair an open in the F-CAN_L or F-CAN A_L wire between the PCM (A10) and DLC (16P) No. 14.