DTC U0100, U0122 (Body Control Module)

DTC U0100  : BCM Lost Communication With ECM/PCM

DTC U0122  : BCM Lost Communication With VSA/ABS

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
• Before you troubleshoot, review the general troubleshooting information .
• According to the detected DTC (s), check for the power circuit and the ground circuit of the control unit which cannot communicate with the body control module.
• Refer to the DTC shown on the display, then inspect the connectors and terminals based on the instructions.

DTC (Body Control Module)

1. CAN gateway system DTC check

   -1. Check for CAN gateway system DTCs with the HDS as follows.

   DTC Description	DTC

   Are any DTCs indicated?

   YES 

   Go to the troubleshooting for CAN gateway system DTC (s) .

   NO 

   Go to step 2.

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

   Does the body control module detect the CAN gateway Bus channels B?

   Bus B is Not Available

   Go to step 3.

   Bus B is Available

   Go to step 4.

3. Open wire check (F-CAN B_H line, F-CAN B_L line)

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

   -2. Disconnect the following connectors.

   CAN gateway 16P connector Body control module connector A (66P)

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

   Test condition	Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected Body control module connector A (66P): disconnected
   Test point 1	CAN gateway 16P connector (female terminals) No. 6:
   Test point 2	Body control module connector A (66P) No. 64

   Test point 1	CAN gateway 16P connector (female terminals) No. 14:
   Test point 2	Body control module connector A (66P) No. 63

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

   Is there continuity?

   YES 

   The F-CAN B_H and F-CAN B_L wires are OK. Check for poor connections or loose terminals at the CAN gateway and the body control module. Substitute a known-good body control module , then recheck. If the DTCs go away after substitution, replace the original body control module .

   NO 

   Repair an open in F-CAN B_H or F-CAN B_L wire between the CAN gateway and the body control module.

4. F-CAN circuit communication check (Transmitting control unit)

   -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

   According to the detected DTC on the following table, make sure that the transmitting control unit detects the CAN gateway Bus channel (s) normally.

   DTC	Transmitting control unit	Detected CAN gateway Bus channel (s) at normal
   U0100	PCM	A, C
   U0122	VSA modulator-control unit	A, B

   Is it detected normally?

   Detected normal

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

   U0100: PCM is Not Available for Bus A

   Go to step 5.

   U0100: PCM is Not Available for Bus C

   Go to step 7.

   U0122: VSA modulator-control unit is Not Available for Bus A

   Go to step 5.

   U0122: VSA modulator-control unit is Not Available for Bus B

   Go to step 6.

5. Open wire check (F-CAN A_H line, F-CAN A_L line)

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

   -2. According to the detected DTC on the following table, disconnect the CAN gateway and transmitting control unit connector (s).

   U0100: Jump the SCS line with the HDS, and wait more than 1 minute.

   SCS short

   DTC	Connector
   -	CAN gateway 16P connector
   U0100	PCM connector A (50P)
   U0122	VSA modulator-control unit 46P connector

   -3. Check for continuity between the receiving control unit and the transmitting control unit on the F-CAN A_H circuit and the F-CAN A_L circuit.

   Test condition

   Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected Transmitting control unit connector (s) for indicated DTCs: disconnected

   DTC	Circuit name	Receiving control unit		Transmitting control unit
   		Connector	Terminal	Connector	Terminal
   U0100	F-CAN A_H	CAN gateway 16P connector (female terminals)	No. 3	PCM connector A (50P)	No. 39
   	F-CAN A_L		No. 11		No. 38
   U0122	F-CAN A_H	CAN gateway 16P connector (female terminals)	No. 3	VSA modulator-control unit 46P connector	No. 20
   	F-CAN A_L		No. 11		No. 21

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

   Is there continuity?

   YES 

   The F-CAN A_H wire and the F-CAN A_L wire are OK.

   According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

   DTC	Operation for transmitting control unit
   U0100	Substitute a known-good PCM , then recheck. If DTC U0100 goes away after substitution, replace the original PCM .
   U0122	Replace the VSA modulator-control unit .

   NO 

   Repair an open in F-CAN A_H or F-CAN A_L wire between the CAN gateway and the transmitting control unit.

6. Open wire check (F-CAN B_H line, F-CAN B_L line)

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

   -2. According to the detected DTC on the following table, disconnect the CAN gateway and transmitting control unit connector.

   DTC	Connector
   -	CAN gateway 16P connector
   U0122	VSA modulator-control unit 46P connector

   -3. Check for continuity between the receiving control unit and the transmitting control unit on the F-CAN B_H circuit and the F-CAN B_L circuit.

   Test condition

   Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected Transmitting control unit connector for indicated DTC: disconnected

   DTC	Circuit name	Receiving control unit		Transmitting control unit
   		Connector	Terminal	Connector	Terminal
   U0122	F-CAN B_H	CAN gateway 16P connector (female terminals):	No. 6	VSA modulator-control unit 46P connector	No. 24
   	F-CAN B_L		No. 14		No. 25

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

   Is there continuity?

   YES 

   The F-CAN B_H wire and the F-CAN B_L wire are OK.

   According to the detected DTC on the following table, replace the control unit based on the instructions (see table).

   DTC	Operation for transmitting control unit
   U0122	Replace the VSA modulator-control unit .

   NO 

   Repair an open in F-CAN B_H or F-CAN B_L wire between the CAN gateway and the transmitting control unit.

7. Open wire check (F-CAN C_H line, F-CAN C_L line)

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

   -2. According to the detected DTC on the following table, disconnect the CAN gateway and transmitting control unit connector.

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

   SCS short

   DTC	Connector
   -	CAN gateway 16P connector
   U0100	PCM connector A (50P)

   -3. Check for continuity between the receiving control unit and the transmitting control unit on the F-CAN C_H circuit and the F-CAN C_L circuit.

   Test condition

   Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected Transmitting control unit connector for indicated DTC: disconnected

   DTC	Circuit name	Receiving control unit		Transmitting control unit
   		Connector	Terminal	Connector	Terminal
   U0100	F-CAN C_H	CAN gateway 16P connector (female terminals):	No. 5	PCM connector A (50P)	No. 37
   	F-CAN C_L		No. 13		No. 36

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

   Is there continuity?

   YES 

   The F-CAN C_H wire and the F-CAN C_L wire are OK.

   According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

   DTC	Operation for transmitting control unit
   U0100	Substitute a known-good PCM , then recheck. If DTC U0100 goes away after substitution, replace the original PCM .

   NO 

   Repair an open in F-CAN C_H or F-CAN C_L wire between the CAN gateway and the transmitting control unit.