DTC B1229 (E and AUTO)

DTC B1229 or DTC indicator E and AUTO  : An Open in the Sunlight 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
   B1229 An open in the sunlight sensor circuit

   Is DTC B1229 or E and AUTO indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure. Check for loose wires or poor connections on the sunlight sensor circuit.

2. Open wire check (TSUN line)

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

   - 2. Disconnect the following connectors.

   Climate control unit connector C (12P)

   Sunlight sensor 2P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector C (12P): disconnected
   	Sunlight sensor 2P connector: disconnected
   Test point 1	Climate control unit connector C (12P) No. 10 - 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	Sunlight sensor 2P connector No. 2

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

   Is there continuity?

   YES 

   The TSUN wire is not open. Go to step 3.

   NO 

   Repair an open in the wire between the climate control unit and the sunlight sensor.

3. Open wire check (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
   	Sunlight sensor 2P 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	Sunlight sensor 2P connector No. 1

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

   Is there continuity?

   YES 

   The SENSOR(COM) wire is not open. Go to step 4.

   NO 

   Repair an open in the wire between the climate control unit and the sunlight sensor.

4. Shorted wire check (TSUN line to power)

   - 1. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Climate control unit connector A (32P): disconnected
   	Climate control unit connector C (12P): disconnected
   	Sunlight sensor 2P connector: disconnected
   Test point 1	Climate control unit connector C (12P) No. 10 - 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 any voltage?

   YES 

   Repair a short to power in the wire between the climate control unit and the sunlight sensor.

   NO 

   The TSUN wire is OK. Go to step 5.

5. Sunlight sensor check

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

   - 2. Reconnect climate control unit connector A (32P).

   - 3. Test the sunlight sensor.

   Is the sunlight sensor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the sunlight sensor - Refer to: Sunlight Sensor Removal and Installation(Without Automatic Wiper), or Sunlight Sensor Removal and Installation(With Automatic Wiper) .