DTC B1226 (B and AUTO)

DTC B1226 or DTC indicator B and AUTO  : A Short in the In-Car Temperature Sensor Circuit

DTC (AC)

1. Problem verification

   - 1. Clear the DTC 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
   B1226 A Short in the In-Car Temperature Sensor Circuit

   Is DTC B1226 or B and AUTO indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure. Check for loose wires or poor connections on the in-car temperature circuit.

2. Shorted wire check (SENS TR line)

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

   - 2. Disconnect the following connectors.

   Climate control unit connector C (12P)

   Humidity/in-car temperature sensor 4P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector C (12P): disconnected
   	Humidity/in-car temperature sensor 4P connector: disconnected
   Test point 1	Climate control unit connector C (12P) No. 8 - 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)
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to body ground in the wire between the climate control unit and the humidity/in-car temperature sensor.

   NO 

   The SENS TR wire is not shorted. Go to step 3.

3. Shorted wire check (SENS TR line to SENSOR(COM) 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
   	Climate control unit connector A (32P): disconnected
   	Climate control unit connector C (12P): disconnected
   	Humidity/in-car temperature sensor 4P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 18 - 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)
   Test point 2	Climate control unit connector C (12P) No. 8 - 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)

   Is there continuity?

   YES 

   Repair a short in the wires between the climate control unit and the humidity/in-car temperature sensor.

   NO 

   The SENS TR wire to SENSOR(COM) wire are not shorted. Go to step 4.

4. In-car temperature sensor check

   - 1. Test the in-car temperature sensor.

   Is the in-car temperature sensor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the humidity/in-car temperature sensor .