DTC Troubleshooting: U0100, U0122
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.
Refer to the DTC code shown on the display, and then inspect the connectors and terminals based on the instructions in the table below.
The DTC may be stored due to the grounding failure or the power source failure at the transmitting control unit
(the grounding inspection and the power source inspection on each control unit are required prior to this checking process).

DTC Description
DTC
U0100 BCM lost communication with ECM/PCM
  
U0122 BCM lost communication with VSA/ABS
  

1.
Problem verification:

Problem verification
?1.
Clear the DTCs with the HDS.


?2.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

?3.
Wait for at least 6 seconds.

?4.
Check for DTCs with the HDS.
DTC Description
DTC
U0100 BCM lost communication with ECM/PCM
  
U0122 BCM lost communication with VSA/ABS
  

Are any DTCs indicated?

     
YES: with CAN gateway
     
     
     
Go to step 2.
     
YES: without CAN gateway
     
     
     
Go to step 8.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals.?
2.
CAN gateway system DTC check:

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
  
U3000-49 CAN Gateway Internal Failure
  

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

     
YES
     
     
     
     
NO
     
     
     
Go to step 3.
3.
F-CAN circuit communication check (Receiving control unit):

F-CAN circuit communication check (Receiving control unit)
?1.
Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.

  

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

     
Bus A is Not Available
     
     
     
Go to step 4.
     
Bus A is Available
     
     
     
Go to step 5.
4.
Open wire check (F-CAN A lines):

Open wire check (F-CAN A lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connectors.
CAN gateway 12P connector
Body control module connector B (36P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 12P connector: disconnected
Body control module connector B (36P): disconnected
Test point 1
CAN gateway 12P connector (female terminals) No. 3:
Test point 2
Body control module connector B (36P) No. 22

Test point 1
CAN gateway 12P connector (female terminals) No. 9:
Test point 2
Body control module connector B (36P) No. 23


Is there continuity?

     
YES
     
     
     
The F-CAN A_H and F-CAN A_L wires are OK. Replace the body control module.?
     
NO
     
     
     
Repair an open in F-CAN A_H or F-CAN A_L wire.?
5.
F-CAN circuit communication check (Transmitting control unit):

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.

  

?2.
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, B
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 6.
     
U0100: PCM is Not Available for Bus B
     
     
     
Go to step 7.
     
U0122: VSA modulator-control unit is Not Available for Bus A
     
     
     
Go to step 6.
     
U0122: VSA modulator-control unit is Not Available for Bus B
     
     
     
Go to step 7.
6.
Open wire check (F-CAN A lines):

Open wire check (F-CAN A lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
U0100: Jump the SCS line with the HDS, and wait more than 1 minute.


?3.
According to the detected DTC on the following table, disconnect the transmitting control unit connector(s).
DTC
Connector
-
CAN gateway 12P connector
U0100
PCM connector A (50P)
U0122
VSA modulator-control unit 46P connector

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 12P connector: disconnected
Transmitting control unit connector(s) for indicated DTCs: disconnected

DTC
Circuit name
Test point 1 (Receiving control unit)
Test point 2 (Transmitting control unit)
Connector
Terminal
Connector
Terminal
U0100
F-CAN A_H
CAN gateway 12P connector (female terminals):
No. 3
PCM connector A (50P)
No. 37
F-CAN A_L
No. 9
No. 36
U0122
F-CAN A_H
CAN gateway 12P connector (female terminals):
No. 3
VSA modulator-control unit 46P connector
No. 40
F-CAN A_L
No. 9
No. 28


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 replace the correspond control unit.?
DTC
Operation for transmitting control unit
U0100
PCM
U0122
VSA modulator-control unit
     
NO
     
     
     
Repair an open in F-CAN A_H or F-CAN A_L wire.?
7.
Open wire check (F-CAN B lines):

Open wire check (F-CAN B lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
U0100: Jump the SCS line with the HDS, and wait more than 1 minute.


?3.
According to the detected DTC on the following table, disconnect the transmitting control unit connector(s).
DTC
Connector
-
CAN gateway 12P connector
U0100
PCM connector A (50P)
U0122
VSA modulator-control unit 46P connector

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 12P connector: disconnected
Transmitting control unit connector(s) for indicated DTCs: disconnected

DTC
Circuit name
Test point 1 (Receiving control unit)
Test point 2 (Transmitting control unit)
Connector
Terminal
Connector
Terminal
U0100
F-CAN B_H
CAN gateway 12P connector (female terminals):
No. 12
PCM connector A (50P)
No. 39
F-CAN B_L
No. 5
No. 38
U0122
F-CAN B_H
CAN gateway 12P connector (female terminals):
No. 12
VSA modulator-control unit 46P connector
No. 46
F-CAN B_L
No. 5
No. 34


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 correspond control unit.?
DTC
Operation for transmitting control unit
U0100
PCM
U0122
VSA modulator-control unit
     
NO
     
     
     
Repair an open in F-CAN B_H or F-CAN B_L wire.?
8.
Open wire check (F-CAN_H line, F-CAN_L line):

Open wire check (F-CAN_H line, F-CAN_L line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Body control module connector B (36P)

?3.
U0100: Jump the SCS line with the HDS, and wait more than 1 minute.


?4.
Disconnect the transmitting control unit connector(s).
Refer to the DTC shown on the display, then disconnect the connector(s) based on the instructions (see table).

DTC
Connector
U0100
PCM connector A (51P)
U0122
VSA modulator-control unit 46P connector

?5.
Check for continuity between the receiving control unit and the transmitting control unit on the F-CAN_H circuit and the F-CAN_L circuit.
Test condition
Receiving control unit connector(s): 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_H
Body control module connector B (36P)
No. 22
PCM connector A (51P)
No. 2
F-CAN_L
No. 23
No. 1
U0122
F-CAN_H
Body control module connector B (36P)
No. 22
VSA modulator-control unit 46P connector
No. 40
F-CAN_L
No. 23
No. 28

Is there continuity?

     
YES
     
     
     
The F-CAN_H wire and the F-CAN_L wire are OK.
Refer to the DTC shown on the display, replace the control unit based on the instructions (see table).?
DTC
Operation for transmitting control unit
U0100
PCM
U0122
VSA modulator-control unit
     
NO
     
     
     
Repair an open in the F-CAN_H wire and/or the F-CAN_L wire.?