Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Honda >> 2014 >> CR-V EX, 2.4L Eng, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Body Control System - DTC Testing >> DTC B121D or DTC indicator 89: Humidity/In-Car Temperature Sensor Communication Error

DTC B121D or DTC indicator 89: Humidity/In-Car Temperature Sensor Communication Error

Fig 1: DTC Troubleshooting Chart (B121D)
G08873234Courtesy of AMERICAN HONDA MOTOR CO., INC.
DTC Description DTC
B121D Humidity/in-car temperature sensor communication error  
  1. Problem verification:

    Is DTC B121D or 89 indicated? 

    YES  : Go to step 2.

    NO  : Intermittent failure. Check for loose wires or poor connections on the humidity/in-car temperature sensor.

  2. Humidity/in-car temperature sensor SENSOR 5V line check:
    • 1. Turn the ignition switch to LOCK (0).
    • 2. Disconnect the following connector.

      Humidity/in-car temperature sensor 4P connector

    • 3. Turn the ignition switch to ON (II).
    • 4. Measure the voltage between test points 1 and 2.

      Test condition IG ON (II)

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit SENSOR 5V

      Test point 1 Humidity/in-car temperature sensor 4P connector No. 1 (LT BLU)

      Test point 2 Body ground

      Fig 2: Measuring Voltage Between Humidity/In-Car Temperature Sensor 4P Connector Terminals 1 And 2
      G08873235Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES  : Go to step 3.

    NO  : Go to step  7.

  3. Open wire check (SENSOR COM line):
    • 1. Turn the ignition switch to LOCK (0).
    • 2. Disconnect the following connector.

      Climate control unit 32P connector

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

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit SENSOR COM

      Test point 1 Climate control unit 32P connector No. 23 (GRY)

      Test point 2 Humidity/in-car temperature sensor 4P connector No. 3 (GRY)

      Fig 3: Checking Continuity Between Humidity/In-Car Temperature Sensor 4P Connector Terminals 1 And 2
      G08873236Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  : The SENSOR COM wire is OK. Go to step 4.

    NO  : Repair an open in the wire between the climate control unit and the humidity/in-car temperature sensor.

  4. Climate control unit HUM CLK, HUM DATA lines check:
    • 1. Connect terminals A and B with a jumper wire.

      Terminal A Humidity/in-car temperature sensor 4P connector No. 2 (ORN)

      Terminal B Humidity/in-car temperature sensor 4P connector No. 4 (RED)

      Fig 4: Identifying Humidity/In-Car Temperature Sensor 4P Connector Terminals
      G08873237Courtesy of AMERICAN HONDA MOTOR CO., INC.
    • 2. Check for continuity between test points 1 and 2.

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Humidity/in-car temperature sensor 4P connector No. 2 and No. 4: jumped

      Test circuit HUM CLK, HUM DATA

      Test point 1 Climate control unit 32P connector No. 4 (ORN)

      Test point 2 Climate control unit 32P connector No. 5 (RED)

      Fig 5: Identifying Climate Control Unit 32P Connector Terminals
      G08873238Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  : Go to step 5.

    NO  : Go to step  8.

  5. Climate control unit HUM DATA line check:
    • 1. Check for continuity between test points 1 and 2.

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Humidity/in-car temperature sensor 4P connector No. 2 and No. 4: jumped

      Test circuit HUM DATA

      Test point 1 Climate control unit 32P connector No. 4 (ORN)

      Test point 2 Body ground

      Fig 6: Checking Continuity Between Climate Control Unit 32P Connector Terminals
      G08873239Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  : Go to step 6.

    NO  : Go to step  9.

  6. Shorted wire check (HUM DATA line):
    • 1. Disconnect the jumper wire.
    • 2. Check for continuity between test points 1 and 2.

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit HUM DATA

      Test point 1 Climate control unit 32P connector No. 4 (ORN)

      Test point 2 Body ground

      Fig 7: Checking Continuity Between Climate Control Unit 32P Connector Terminals 1 And 2
      G08873240Courtesy of AMERICAN HONDA MOTOR CO., INC.

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

  7. Open wire check (SENSOR 5V line):
    • 1. Turn the ignition switch to LOCK (0).
    • 2. Disconnect the following connector.

      Climate control unit 32P connector

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

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit SENSOR 5V

      Test point 1 Climate control unit 32P connector No. 17 (LT BLU)

      Test point 2 Humidity/in-car temperature sensor 4P connector No. 1 (LT BLU)

      Fig 8: Checking Continuity Between Humidity/In-Car Temperature Sensor 4P Connector Terminals 1 And 2
      G08873241Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

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

    NO  : Repair an open in the wire between the climate control unit and the humidity/in-car temperature sensor.

  8. Open wire check (HUM DATA line):
    • 1. Disconnect the jumper wire.
    • 2. Check for continuity between test points 1 and 2.

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit HUM DATA

      Test point 1 Climate control unit 32P connector No. 4 (ORN)

      Test point 2 Humidity/in-car temperature sensor 4P connector No. 2 (ORN)

      Fig 9: Checking Continuity Between Humidity/In-Car Temperature Sensor 4P Connector Terminals 1 And 2
      G08873242Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  : Repair an open in the wire between the climate control unit and the humidity/in-car temperature sensor.

    NO  : Repair an open in the wire between the climate control unit and the humidity/in-car temperature sensor.

  9. Shorted wire check (HUM CLK line to HUM DATA line):
    • 1. Disconnect the jumper wire.
    • 2. Check for continuity between test points 1 and 2.

      Test condition IG LOCK (0)

      Climate control unit 32P connector: disconnected

      Humidity/in-car temperature sensor 4P connector: disconnected

      Test circuit HUM CLK, HUM DATA

      Test point 1 Climate control unit 32P connector No. 4 (ORN)

      Test point 2 Climate control unit 32P connector No. 5 (RED)

      Fig 10: Checking Continuity Between Climate Control Unit 32P Connector Terminals 1 And 2
      G08873243Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

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

    NO  : Go to step 10.

  10. Climate control unit check:
    • 1. Reconnect the climate control unit 32P connector.
    • 2. Connect terminals A and B with a jumper wire.

      Terminal A Humidity/in-car temperature sensor 4P connector No. 2 (ORN)

      Terminal B Humidity/in-car temperature sensor 4P connector No. 4 (RED)

      Fig 11: Identifying Humidity/In-Car Temperature Sensor 4P Connector Terminals
      G08873244Courtesy of AMERICAN HONDA MOTOR CO., INC.
    • 3. Turn the ignition switch to ON (II).
    • 4. Press and hold the AUTO and ON/OFF buttons.
      Fig 12: Identifying Mode Indicator
      G08873245Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Does the mode indicator turn on? 

    YES  : REPLACE THE HUMIDITY/IN-CAR TEMPERATURE SENSOR .

    NO  : REPLACE THE CLIMATE CONTROL UNIT .

scientia non olet · About Mike's Workshop Manuals