DTC U0122: Gauge Control Module Lost Communication With VSA Modulator-Control Unit

DTC (Gauge Control Module)

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC ChecksBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS)Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not CommunicatingBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Won't Shut OFFBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode D - No DTCs and Output Won't Turn ON .
• If you have any loss of communication DTCs for the PCM, troubleshoot those DTCs first.

• 1. 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
  U0122 Gauge control module lost communication with VSA modulator-control unit

  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:

  1. Check the following fuses.

  Fuse	No. B24 (7.5 A)
  Location	Under-dash fuse/relay box

  Is each fuse OK?

  YES 

  Go to step 3.

  NO 

  Replace the fuse. If the fuse blows again, repair a short to ground in the No. B24 (7.5 A) fuse circuit.

• 3. 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 line):

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

  2. Check for continuity between test points 1 and 2 individually.

  Test condition	Vehicle OFF (LOCK) modeVSA modulator-control unit 38P connector: disconnected
  Test point 1	VSA modulator-control unit 38P connector No. 1 (BLK)
  Test point 2	Body ground

  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 5.

  NO 

  Repair an open or high resistance in the ground wire or poor ground (G201).

• 5. Open wire check (F-CAN lines):

  1. Disconnect the following connector.

  Gauge control module connector A (32P)

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

  Test condition	Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Gauge control module connector A (32P): disconnected
  Test point 1	VSA modulator-control unit 38P connector No. 38
  Test point 2	Gauge control module connector A (32P) No. 19

  Test point 1	VSA modulator-control unit 38P connector No. 26
  Test point 2	Gauge control module connector A (32P) No. 20

  Is there continuity?

  YES 

  The F-CAN wires are OK. Replace the gauge control module .

  NO 

  An open or poor connection in the F-CAN wires between the VSA modulator-control unit and the gauge control module.