DTC U1290

DTC U1290  : Climate Control Unit Lost Communication With Seat Heater Control Unit

DTCs (AC)

1. Problem verification

   - 1. Clear the DTCs with the HDS.

   - 2. Turn the vehicle to the OFF (LOCK) mode then the ON mode.

   - 3. Do the Self-Diagnostic Function with the HDS or the climate control unit.

   - 4. Check for DTCs.

   DTC Description	DTC
   U1290 Climate Control Unit Lost Communication With Seat Heater Control Unit

   Is DTC U1290 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 (ventilated seat control unit power and ground, B-CAN lines)

   - 1. Select B-CAN Control Units Information from the Body Electrical System Select menu, then select Check Connected Control Units.

   - 2. Check the DETECT/Not available information of the Seat Heater Control Unit.

   Is DETECT indicated?

   YES 

   Go to step 3.

   NO 

   Go to step 4.

3. Open wire check (B-CAN_H line)

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

   - 2. Disconnect the following connectors.

   Ventilated seat 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
   	Ventilated seat control unit 14P connector: disconnected
   	Climate control unit connector A (32P): disconnected
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 11:
   Test point 2	Climate control unit connector A (32P) No. 23 - Refer to: Climate Control Unit Connector For Inputs and Outputs (2019 2020 2021), or Climate Control Unit Connector For Inputs and Outputs (2016 2017 2018)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair an open or poor connection in the B-CAN_L wire between the climate control unit and the ventilated seat control unit.

   NO 

   Repair an open or poor connection in the B-CAN_H wire between the climate control unit and the ventilated seat control unit.

4. Fuse check

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

   - 2. Check the following fuse.

   Fuse	No. D1 - Refer to: Fuse to Components Index (2019 2020 2021: Without Auto Idle Stop System) or Fuse to Components Index (2019 2020 2021: With Auto Idle Stop System), or Fuse to Components Index (2016 2017 2018: With Auto Idle Stop System), or Fuse to Components Index (2016 2017 2018: With Auto Idle Stop System) .
   	No. C29 - Refer to: Fuse to Components Index (2019 2020 2021: Without Auto Idle Stop System) or Fuse to Components Index (2019 2020 2021: With Auto Idle Stop System), or Fuse to Components Index (2016 2017 2018: With Auto Idle Stop System), or Fuse to Components Index (2016 2017 2018: With Auto Idle Stop System) .

   Is the fuse OK?

   YES 

   Go to step 5.

   NO 

   Replace the fuse, and recheck. If the fuse blow again, repair a short in the No. D1 or C29 fuse circuit.

5. Open wire check (+B H/SEAT UNIT line)

   - 1. Disconnect the following connector.

   Ventilated seat control unit 14P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Ventilated seat control unit 14P connector: disconnected
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 2:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there battery voltage?

   YES 

   The +B H/SEAT UNIT wire is OK. Go to step 6.

   NO 

   Repair an open in the +B H/SEAT UNIT wire.

6. Open wire check (IG1 METER(DC/DC) line)

   - 1. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Ventilated seat control unit 14P connector: disconnected
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 9:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there battery voltage?

   YES 

   The IG1 METER(DC/DC) wire is OK. Go to step 7.

   NO 

   Repair an open in the IG1 METER(DC/DC) wire.

7. Open wire check (GND line)

   - 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
   	Ventilated seat control unit 14P connector: disconnected
   Test circuit 1
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 4:
   Test point 2	Body ground

   Test circuit 2
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 14:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The GND wire is OK. Go to step 8

   NO 

   Check for an open in the wire(s) between the ventilated seat control unit and body ground. If the wire(s) is OK, check for poor ground at G601.

8. Open wire check (B-CAN_H line)

   - 1. Disconnect the following connector.

   Climate control unit connector A (32P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Ventilated seat control unit 14P connector: disconnected
   	Climate control unit connector A (32P): disconnected
   Test point 1	Ventilated seat control unit 14P connector (female terminals) No. 11:
   Test point 2	Climate control unit connector A (32P) No. 23 - Refer to: Climate Control Unit Connector For Inputs and Outputs (2019 2020 2021), or Climate Control Unit Connector For Inputs and Outputs (2016 2017 2018)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair an open or poor connection in the B-CAN_L wire between the climate control unit and the ventilated seat control unit.

   NO 

   Repair an open or poor connection in the B-CAN_H wire between the climate control unit and the ventilated seat control unit.