DTC Troubleshooting: B1225 (A-B1), B1225 (01)

DTC B1225 or DTC screen A-B1 or DTC indicator 01  : An open in the in-car temperature sensor circuit

DTCs (AC)

1. Problem verification

   -1. Clear the DTC with the HDS.

   -2. Turn the vehicle to the OFF (LOCK) mode and 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
   B1225 An open in the in-car temperature sensor circuit

   Is DTC B1225 or Error on the DTC screen A-B1 (climate control panel without display) or 01 (climate control panel with display) indicated?

   YES 

   Go to step 2.

   NO 

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

2. Open wire check (TR line)

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

   -2. Disconnect the following connectors.

   Climate control unit connector A (32P)

   In-car temperature sensor 2P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconected
   	In-car temperature sensor 2P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 27
   Test point 2	In-car temperature sensor 2P connector (female terminals) No. 2:

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

   Is there continuity?

   YES 

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

   NO 

   Repair an open in the TR wire.

3. Open wire check (SENSOR COM line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	In-car temperature sensor 2P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 12
   Test point 2	In-car temperature sensor 2P connector (female terminals) No. 1:

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

   Is there continuity?

   YES 

   The SENSER COM wire is OK. Go to step 4.

   NO 

   Repair an open in the SENSOR COM wire.

4. Shorted wire check (TR line to power)

   -1. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Climate control unit connector A (32P): disconnected
   	In-car temperature sensor 2P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 27
   Test point 2	Body ground

   Is there any voltage?

   YES 

   Repair a short to power in the TR wire.

   NO 

   The TR wire is OK. Go to step 5.

5. In-car temperature sensor check

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

   -2. Test the in-car temperature sensor .

   Is the in-car temperature sensor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the in-car temperature sensor .