DTC Troubleshooting: U0100, U0122
DTC U0100: Power Control Unit Lost Communication with PCM
DTC U0122: Power Control Unit Lost Communication with VSA Modulator-Control Unit (VSA Message)
NOTE:
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 keyless access control unit.
Refer to the DTC shown on the display, then inspect the connectors and terminals based on the instructions.

DTC Description
DTC
U0100 Power Control Unit Lost Communication with PCM
  
U0122 Power Control Unit Lost Communication with ABS/VSA Modulator-Control Unit
  

1.
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 2.
2.
F-CAN circuit communication check:

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.

  

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

     
Bus A is Not Available
     
     
     
Go to step 3.
     
Bus A is Available
     
     
     
Go to step 4.
3.
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 16P connector
Keyless access control unit connector C (20P)

?3.
Check for continuity between test points 1 and 2 respectively.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 16P connector: disconnected
Keyless access control unit connector C (20P): disconnected
Test point 1
CAN gateway 16P connector No. 3
Test point 2
Keyless access control unit connector C (20P) No. 2

Test point 1
CAN gateway 16P connector No. 11
Test point 2
Keyless access control unit connector C (20P) No. 12


Is there continuity?

     
YES
     
     
     
The F-CAN A_H and F-CAN A_L wires are OK. Check for poor connections or loose terminals at the CAN gateway and the keyless access control unit. Substitute a known-good keyless access control unit, then recheck. If the DTC U0100 goes away and the keyless access control unit was substituted, replace the original keyless access control unit.?
     
NO
     
     
     
Repair an open in F-CAN A_H or F-CAN A_L wire between the CAN gateway and the keyless access control unit.?
4.
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
U0122
VSA modulator-control unit
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.
     
U0122: VSA modulator-control unit is Not Available for Bus B
     
     
     
Go to step 6.
5.
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 16P connector
U0100
PCM connector A (51P)

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 16P 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 16P connector
No. 3
PCM connector A (51P)
No. 2
F-CAN A_L
No. 11
No. 1


Is there continuity?

     
YES
     
     
     
The F-CAN A_H wire and the F-CAN A_L wire are OK.
Refer to the DTC shown on the display, 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 and the PCM was substituted, replace the original PCM.
     
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 lines):

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

?2.
According to the detected DTC on the following table, disconnect the transmitting control unit connector(s).
DTC
Connector
-
CAN gateway 16P connector
U0122
VSA modulator-control unit 38P connector

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
CAN gateway 16P 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
U0122
F-CAN B_H
CAN gateway 16P connector
No. 6
VSA modulator-control unit 38P connector
No. 38
F-CAN B_L
No. 14
No. 26


Is there continuity?

     
YES
     
     
     
The F-CAN B_H wire and the F-CAN B_L wire are OK.
Refer to the DTC shown on the display, substitute or 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.?