DTC Troubleshooting: U0122
DTC U0122: Power Control Unit Lost Communication With VSA Modulator-Control Unit (VSA Message)
DTC Description
DTC
U0122 Power Control Unit Lost Communication with VSA Modulator-Control Unit(VSA Message)
  

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

1.
Problem verification:

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


?2.
Press the engine start/stop button to select the OFF mode and then the ON mode.

?3.
Wait for at least 6 seconds.

?4.
Check for DTCs with the HDS.
DTC Description
DTC
U0122 Power Control Unit Lost Communication with VSA Modulator-Control Unit(VSA Message)
  

Is DTC U0122 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for loose or poor connections.?
2.
Fuse check:

Fuse check
?1.
Check the following fuse.
Fuse
No. B10 (7.5 A)
Location
Under-dash fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 3.
     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
Replace the fuse. If the fuse blows again, repair a short to ground in the No. B10 (7.5 A) fuse circuit.?
3.
Open wire check (IG1 VSA/ABS line):

Open wire check (IG1 VSA/ABS line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Press the engine start/stop button to select the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
VSA modulator-control unit 21P connector: disconnected
Test circuit
IG1 VSA/ABS
Test point 1
VSA modulator-control unit 21P connector No. 6 (YEL)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG1 VSA/ABS wire is OK. Go to step 4.
     
NO
     
     
     
Repair an open or high resistance in the wire.?
4.
Open wire check (GND line):

Open wire check (GND line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Check for continuity between test points 1 and 2 individually.
Test condition
OFF mode
VSA modulator-control unit 21P connector: disconnected
Test circuit
GND
Test point 1
VSA modulator-control unit 21P connector No. 1 (BLK)
Test point 2
Body ground

Test circuit
GND
Test point 1
VSA modulator-control unit 21P connector No. 2 (BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
The GND wires are OK. Go to step 5.
     
NO
     
     
     
Repair an open or high resistance in the ground wire or poor ground (G202).?
5.
Open wire check (F-CAN lines):

Open wire check (F-CAN lines)
?1.
Disconnect the following connector.

?2.
Check for continuity between test points 1 and 2 respectively.
Test condition
OFF mode
VSA modulator-control unit 21P connector: disconnected
Keyless access control unit connector C (24P): disconnected
Test circuit
F-CAN_H
Test point 1
VSA modulator-control unit 21P connector No. 8 (WHT)
Test point 2
Keyless access control unit connector C (24P) No. 4 (WHT)

Test circuit
F-CAN_L
Test point 1
VSA modulator-control unit 21P connector No. 15 (RED)
Test point 2
Keyless access control unit connector C (24P) No. 5 (RED)


Is there continuity?

     
YES
     
     
     
The F-CAN wires are OK. Replace the keyless access control unit.?
     
NO
     
     
     
An open or poor connection in the F-CAN wires between the VSA modulator-control unit and the keyless access control unit.?
6.
Open wire check (IG1 VSA/ABS line):

Open wire check (IG1 VSA/ABS line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Press the engine start/stop button to select the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
VSA modulator-control unit 38P connector: disconnected
Test circuit
IG1 VSA/ABS
Test point 1
VSA modulator-control unit 38P connector No. 36 (YEL)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG1 VSA/ABS wire is OK. Go to step 7.
     
NO
     
     
     
Repair an open or high resistance in the wire.?
7.
Open wire check (GND line):

Open wire check (GND line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Check for continuity between test points 1 and 2 individually.
Test condition
OFF mode
VSA modulator-control unit 38P connector: disconnected
Test circuit
GND
Test point 1
VSA modulator-control unit 38P connector No. 1 (BLK)
Test point 2
Body ground

Test circuit
GND
Test point 1
VSA modulator-control unit 38P connector No. 3 (BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
The GND wires are OK. Go to step 8.
     
NO
     
     
     
Repair an open or high resistance in the ground wire or poor ground (G202).?
8.
Open wire check (F-CAN lines):

Open wire check (F-CAN lines)
?1.
Disconnect the following connector.

?2.
Check for continuity between test points 1 and 2 respectively.
Test condition
OFF mode
VSA modulator-control unit 38P connector: disconnected
Keyless access control unit connector C (24P): disconnected
Test circuit
F-CAN_H
Test point 1
VSA modulator-control unit 38P connector No. 38 (WHT)
Test point 2
Keyless access control unit connector C (24P) No. 4 (WHT)

Test circuit
F-CAN_L
Test point 1
VSA modulator-control unit 38P connector No. 26 (RED)
Test point 2
Keyless access control unit connector C (24P) No. 5 (RED)


Is there continuity?

     
YES
     
     
     
The F CAN wires are OK. Replace the keyless access control unit.?
     
NO
     
     
     
An open or poor connection in the F-CAN wires between the VSA modulator-control unit and the keyless access control unit.?