DTC U0101-00

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2020 Acura RLX, 2019 Acura RLX, 2018 Acura RLX, 2017 Acura RLX, and 2016 Acura RLX. However, it is still accessible from the selected car via links, so may be relevant.

DTC U0101-00 : Lost Communication With The PCM/TCM

NOTE: Before you troubleshoot, review the general troubleshooting information .

CAN gateway system DTC check

-1. Turn the vehicle to the ON mode.

-2. Check for CAN gateway system DTCs with the HDS.

DTC Description	DTC
U0029-00 CAN Gateway F-CAN ch A Bus Off
U0047-00 CAN Gateway F-CAN ch B Bus Off
U0056-00 CAN Gateway F-CAN ch C Bus Off
U3000-49 CAN Gateway Internal Failure

Is DTC U0029-00, U0047-00, U0056-00, and/or U3000-49 indicated?

YES

Go to the indicated DTCs troubleshooting .

Go to step 2.

F-CAN circuit communication check
-1. Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.

F-CAN Bus Connected Unit Check

Which result is indicated?

PCM (Bus A) is Not Available

Go to step 3.

PCM (Bus B) is Not Available

Go to step 4.

Multipurpose camera unit (Bus B) is Not Available

Go to step 5.

Multipurpose camera unit (Bus C) is Not Available

Go to step 6.

Multipurpose camera unit and PCM are Detected

Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting . If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

Open wire check (F-CAN A_L, F-CAN A_H lines)

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

-2. Short the SCS line with the HDS.

-3. Disconnect the following connectors.

CAN gateway 24P connector

PCM connector A (51P)

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	PCM connector A (51P): disconnected
Test point 1	CAN gateway 24P connector No. 14
Test point 2	PCM connector A (51P) No. 10

Test point 1	CAN gateway 24P connector No. 15
Test point 2	PCM connector A (51P) No. 9

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

Is there continuity?

YES

Check for loose terminals in the CAN gateway 24P connector and PCM connector A (51P). If they are OK, update the PCM if it does not have the latest software , or substitute a known-good PCM , then recheck. If DTC U0101-00 is not indicated after substitution, replace the PCM .

Repair an open in the wire between the CAN gateway and the PCM.

Open wire check (F-CAN B_L, F-CAN B_H lines)

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

-2. Short the SCS line with the HDS.

-3. Disconnect the following connectors.

CAN gateway 24P connector

PCM connector A (51P)

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	PCM connector A (51P): disconnected
Test point 1	CAN gateway 24P connector No. 11
Test point 2	PCM connector A (51P) No. 11

Test point 1	CAN gateway 24P connector No. 12
Test point 2	PCM connector A (51P) No. 12

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

Is there continuity?

YES

Repair an open in the wire between the CAN gateway and the PCM.

Open wire check (F-CAN B_L, F-CAN B_H lines)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

Multipurpose camera unit 20P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	Multipurpose camera unit 20P connector: disconnected
Test point 1	CAN gateway 24P connector No. 11
Test point 2	Multipurpose camera unit 20P connector No. 2

Test point 1	CAN gateway 24P connector No. 10
Test point 2	Multipurpose camera unit 20P connector No. 13

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

Is there continuity?

YES

The F-CAN B_L and F-CAN B_H wires are OK. Go to step 7.

Repair an open in the wire between the CAN gateway and the multipurpose camera unit.

Open wire check (F-CAN C_L, F-CAN C_H lines)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

Multipurpose camera unit 20P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	Multipurpose camera unit 20P connector: disconnected
Test point 1	CAN gateway 24P connector No. 9
Test point 2	Multipurpose camera unit 20P connector No. 4

Test point 1	CAN gateway 24P connector No. 8
Test point 2	Multipurpose camera unit 20P connector No. 15

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

Is there continuity?

YES

The F-CAN C_L and F-CAN C_H wires are OK. Go to step 7.

Repair an open in the wire between the CAN gateway and the multipurpose camera unit.

Multipurpose camera unit check (update)
-1. Reconnect the following connectors.

CAN gateway 24P connector

Multipurpose camera unit 20P connector

-2. Update the multipurpose camera unit if it does not have the latest software .

-3. Turn the vehicle to the OFF (LOCK) mode.

-4. Turn the vehicle to the ON mode, then wait for at least 5 seconds.

-5. Check for DTCs with the HDS.

Is DTC U0101-00 indicated?

YES

Check for loose terminals in the multipurpose camera unit 20P connector. If the multipurpose camera unit was updated and the symptom/indication is still present, replace the multipurpose camera unit .

NO

Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTC's troubleshooting.