DTC B1223 (L and MODE)

DTC B1223 or DTC indicator L and MODE  : A Problem in the Rear Blower Motor 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
   B1223 A problem in the rear blower motor circuit

   Is DTC B1223 or L and MODE indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure. Check for loose wires or poor connections on the rear blower motor circuit.

2. Fuse check

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

   - 2. Check the following fuse.

   Fuse	No. A1-2 (30 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 3.

   NO 

   Replace the fuse, and recheck. If fuse blows again, repair a short in the No. A1-2 (30 A) fuse circuit.

3. Rear blower motor power circuit check (RR BLOWER MTR+ line)

   - 1. Disconnect the following connector.

   Rear blower motor 2P connector

   - 2. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Rear blower motor 2P connector: disconnected
   Test point 1	Rear blower motor 2P connector No. 2
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   Go to step 4.

   NO 

   Go to step 12.

4. Blower motor operation check (RR BLOWER MTR- line)

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

   - 2. Reconnect the rear blower motor 2P connector.

   - 3. Connect terminals A and B with a jumper wire.

   Terminal A	Rear blower motor 2P connector No. 1
   Terminal B	Body ground

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

   - 4. Turn the vehicle to the ON mode.

   Does the rear blower motor run at high speed?

   YES 

   Go to step 5.

   NO 

   Replace the rear blower motor - Refer to: Blower Motor Removal and Installation, or Rear Blower Motor Removal and Installation .

5. Open wire check (SGND line)

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

   - 2. Disconnect the jumper wire.

   - 3. Disconnect the following connector.

   Rear blower power transistor 4P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Rear blower power transistor 4P connector: disconnected
   Test point 1	Rear blower power transistor 4P connector No. 3
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   The SGND wire is OK. Go to step 6.

   NO 

   Check for an open in the wire between the rear blower power transistor and body ground. If the wire is OK, check for poor ground at G201.

6. Open wire check (RR BLOWER MTR- line)

   - 1. Connect terminals A and B with a jumper wire.

   Terminal A	Rear blower power transistor 4P connector No. 3
   Terminal B	Rear blower power transistor 4P connector No. 4

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

   - 2. Turn the vehicle to the ON mode.

   Does the rear blower motor run at high speed?

   YES 

   The RR BLOWER MTR- wire is OK. Go to step 7.

   NO 

   Repair an open in the wire between the rear blower power transistor and the rear blower motor.

7. Shorted wire check (R-BLW-V line)

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

   - 2. Disconnect the jumper wire.

   - 3. Disconnect the following connector.

   Climate control unit connector A (32P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	Rear blower power transistor 4P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 29 - 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 rear blower power transistor.

   NO 

   The R-BLW-V wire is not shorted. Go to step 8.

8. Shorted wire check (R-BLW-G line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	Rear blower power transistor 4P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 30 - 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 rear blower power transistor.

   NO 

   The R-BLW-G wire is not shorted. Go to step 9.

9. Open wire check (R-BLW-G line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	Rear blower power transistor 4P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 30 - 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	Rear blower power transistor 4P connector No. 1

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

   Is there continuity?

   YES 

   The R-BLW-G wire is OK. Go to step 10.

   NO 

   Repair an open in the wire between the climate control unit and the rear blower power transistor.

10. Open wire check (R-BLW-V line)

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

    Test condition	Vehicle OFF (LOCK) mode
    	Climate control unit connector A (32P): disconnected
    	Rear blower power transistor 4P connector: disconnected
    Test point 1	Climate control unit connector A (32P) No. 29 - 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	Rear blower power transistor 4P connector No. 2

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

    Is there continuity?

    YES 

    The R-BLW-V wire is OK. Go to step 11.

    NO 

    Repair an open in the wire between the climate control unit and the rear blower power transistor.

11. Rear blower power transistor check

    - 1. Test the rear blower power transistor.

    Is the rear blower power transistor OK?

    YES 

    Replace the climate control unit .

    NO 

    Replace the rear blower power transistor - Refer to: Blower Power Transistor Removal and Installation, or Rear Blower Power Transistor Removal and Installation .

    NOTE: If the rear blower power transistor is faulty, check the blower motor for damage. If necessary, replace the rear blower motor - Refer to: Blower Motor Removal and Installation, or Rear Blower Motor Removal and Installation .
12. Rear blower motor relay check

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

    - 2. Remove the rear blower motor relay from the auxiliary under-dash relay holder D, and test it.

    Is the relay OK?

    YES 

    Go to step 13.

    NO 

    Replace the rear blower motor relay.

13. Open wire check (+B RR BLOWER line)

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

    Test condition	Vehicle OFF (LOCK) mode
    	Rear blower motor relay: disconnected
    Test point 1	Rear blower motor relay 4P socket No. 1
    Test point 2	Body ground

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

    Is there battery voltage?

    YES 

    The +B RR BLOWER line is OK. Go to step 14.

    NO 

    Repair an open in the wire between the No. A1-2 (30 A) fuse in the under-hood fuse/relay box and the rear blower motor relay. If the wire is OK, replace the under-hood fuse/relay box .

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

    - 1. Turn the vehicle to the ON mode.

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

    Test condition	Vehicle ON mode
    	Rear blower motor relay: disconnected
    Test point 1	Rear blower motor relay 4P socket No. 3
    Test point 2	Body ground

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

    Is there battery voltage?

    YES 

    The IG2 A/C wire is OK. Go to step 15.

    NO 

    Repair an open in the wire between the No. C23 (7.5 A) fuse in the under-dash fuse/relay box and the rear blower motor relay.

15. 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
    	Rear blower motor relay: disconnected
    Test point 1	Rear blower motor relay 4P socket No. 4
    Test point 2	Body ground

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

    Is there continuity?

    YES 

    Repair an open in the wire between the rear blower motor relay and the rear blower motor.

    NO 

    Check for an open in the wire between the rear blower motor relay and body ground. If the wire is OK, check for poor ground at G405.