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: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A.

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTCs with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

?4.
Wait for at least 6 seconds.

?5.
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. C27 (7.5 A)
Location
Under-dash fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Replace the fuse. If the fuse blows again, repair a short to ground in the No. C27 (7.5 A) fuse circuit.?
3.
Open wire check (IG1 VSA/ABS line):

Open wire check (IG1 VSA/ABS line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
VSA modulator-control unit 38P connector

?3.
Turn the vehicle to the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
VSA modulator-control unit 38P connector: disconnected
Test point 1
VSA modulator-control unit 38P connector No. 36
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 lines):

Open wire check (GND lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

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

Test point 1
VSA modulator-control unit 38P connector No. 3
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(s) or poor ground (G201).?
5.
Open wire check (F-CAN lines):

Open wire check (F-CAN lines)
?1.
Disconnect the following connector.
Keyless access control unit connector C (20P)

?2.
Check for continuity between test points 1 and 2 respectively.
Test condition
Vehicle OFF (LOCK) mode
VSA modulator-control unit 38P connector: disconnected
Keyless access control unit connector C (20P): disconnected
Test point 1
VSA modulator-control unit 38P connector No. 26
Test point 2
Keyless access control unit connector C (20P) No. 12


Is there continuity?

     
YES
     
     
     
The F-CAN wires are OK. Replace the keyless access control unit.?
     
NO
     
     
     
An open or poor connection in the wire(s).?