DTC : U1064

DTC U1064  : Seat heater control unit lost communication with climate control unit (second row seat)

DTC (Second Row Seat Heater Control Unit)

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Go to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .
• The seat heater control unit does not turn on the seat heater until the seat core temperature is 85 degrees or less. Make sure the seat core temperature is below 85 degrees before troubleshooting.

1. Problem verification

   -1. Clear the DTCs with the HDS.

   Clear DTCs

   - 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
   U1064 Seat heater control unit lost communication with climate control unit (second row seat)

   Is DTC U1064 indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for loose or poor connections.

2. Determine possible failure area (climate control unit power and ground, B-CAN line)

   -1. Select B-CAN CONTROL UNITS INFORMATION from the BODY ELECTRICAL SYSTEM SELECT menu, and then select CHECK CONNECTED CONTROL UNITS.

   - 2. Check the DETECT/NOT AVAILABLE information of the CLIMATE CONTROL/HVAC CONTROL UNIT.

   Is DETECT indicated?

   YES 

   Go to step 7.

   NO 

   Go to step 3.

3. Fuse check

   -1. Check the following fuses.

   Fuse	No. C23 (7.5 A)
   Location	Under-dash fuse/relay box

   Is each fuse OK?

   YES 

   Go to step 4.

   NO 

   Replace the fuse. If the fuse blows again, repair a short to ground in the No. C23 (7.5 A) fuse circuit.

4. Open wire check (IG2 A/C line)

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

   - 2. Disconnect the following connector.

   Climate control unit connector A (32P)

   - 3. Turn the vehicle to the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode Climate control unit connector A (32P): disconnected
   Test point 1	Climate control unit connector A (32P) No. 1 - Refer to: Climate Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Climate Control Unit Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   The IG2 A/C wire is OK. Go to step 5.

   NO 

   Repair an open or high resistance in the wire.

5. Open wire check (GND lines)

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

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

   Test condition	Vehicle OFF (LOCK) mode Climate control unit connector A (32P): disconnected
   Test point 1	Climate control unit connector A (32P) No. 17 - Refer to: Climate Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Climate Control Unit Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Is there continuity?

   YES 

   The GND wires is OK. Go to step 6.

   NO 

   Repair an open or high resistance in the ground wire or poor ground (G405).

6. Open wire check (B-CAN lines)

   -1. Disconnect the following connector.

   Second row seat heater control unit 14P connector

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

   Test condition	Vehicle OFF (LOCK) mode Second row seat heater control unit 14P connector: disconnected Climate control unit connector A (32P): disconnected
   Test point 1	Second row seat heater control unit 14P connector No. 11 - Refer to: Second Row Seat Heater Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Second Row Seat Heater Control Unit Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Climate control unit connector A (32P) No. 23 - Refer to: Climate Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Climate Control Unit Connector for Inputs and Outputs (2019 2020 2021) .

   Is there continuity?

   YES 

   An open or poor connection in the B-CAN_L wire between the second row seat heater control unit and the climate control unit.

   NO 

   An open or poor connection in the B-CAN_H wire between the second row seat heater control unit and the climate control unit.

7. Open wire check (B-CAN lines)

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

   - 2. Disconnect the following connectors.

   Second row seat heater control unit 14P connector

   Climate control unit connector A (32P)

   - 3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Second row seat heater control unit 14P connector: disconnected Climate control unit connector A (32P): disconnected
   Test point 1	Second row seat heater control unit 14P connector No. 11 - Refer to: Second Row Seat Heater Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Second Row Seat Heater Control Unit Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Climate control unit connector A (32P) No. 23 - Refer to: Climate Control Unit Connector for Inputs and Outputs (2016 2017 2018) or Climate Control Unit Connector for Inputs and Outputs (2019 2020 2021) .

   Is there continuity?

   YES 

   An open or poor connection in the B-CAN_L wire between the second row seat heater control unit and the climate control unit.

   NO 

   An open or poor connection in the B-CAN_H wire between the second row seat heater control unit and the climate control unit.