DTC U1101

DTC U1101 : F-CAN Malfunction (PCM - ACM)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information .

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
U1101 F-CAN Malfunction (PCM - ACM)

DTC (PGM-FI)

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 troubleshooting for CAN gateway system DTC(s) .

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 5.

ACM is Not Available

Go to step 7.

PCM and ACM are Detected

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the engine mount control unit, the CAN gateway, and the PCM.

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.

-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 circuit	F-CAN A_H
Test point 1	CAN gateway 24P connector No. 14 (BLU)
Test point 2	PCM connector A (51P) No. 9 (BLU)

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

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) 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 24P connector: disconnected
	PCM connector A (51P): disconnected
Test circuit	F-CAN A_L
Test point 1	CAN gateway 24P connector No. 15 (PNK)
Test point 2	PCM connector A (51P) No. 10 (PNK)

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. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC U1101 goes away and the PCM was updated, troubleshooting is complete. If DTC U1101 goes away and the PCM was substituted, replace the original PCM .

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

Open wire check (F-CAN B_H line)

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

-2. Jump 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 circuit	F-CAN B_H
Test point 1	CAN gateway 24P connector No. 11 (LT BLU)
Test point 2	PCM connector A (51P) No. 11 (LT BLU)

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

Is there continuity?

YES

Go to step 6.

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

Open wire check (F-CAN B_L line)

-1. 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 circuit	F-CAN B_L
Test point 1	CAN gateway 24P connector No. 10 (GRY)
Test point 2	PCM connector A (51P) No. 12 (GRY)

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

Is there continuity?

YES

The F-CAN B_L wire is OK. Check for poor connections or loose terminals at the CAN gateway and the PCM. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC U1101 goes away and the PCM was updated, troubleshooting is complete. If DTC U1101 is not indicated the PCM was substituted, replace the original PCM .

Repair an open in the F-CAN B_L wire between the PCM (A12) and the CAN gateway.

Open wire check (F-CAN A_H line)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

Engine mount control unit 16P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	Engine mount control unit 16P connector: disconnected
Test circuit	F-CAN A_H
Test point 1	CAN gateway 24P connector No. 14 (BLU)
Test point 2	Engine mount control unit 16P connector No. 13 (BLU)

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

Is there continuity?

YES

The F-CAN A_H wire is OK. Go to step 8.

Repair an open in the F-CAN A_H wire between the CAN gateway and the engine mount control unit.

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 24P connector: disconnected
	Engine mount control unit 16P connector: disconnected
Test circuit	F-CAN A_L
Test point 1	CAN gateway 24P connector No. 15 (PNK)
Test point 2	Engine mount control unit 16P connector No. 15 (PNK)

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 engine mount control unit. Substitute a known-good engine mount control unit , then recheck. If DTC U1101 goes away and the engine mount control unit was substituted, replace the original engine mount control unit .

Repair an open in the F-CAN A_L wire between the CAN gateway and the engine mount control unit.