DTC B28C6: Heater Control

DTC detecting condition: 

When the stereo camera detected defogging control abnormality.

Trouble symptom: 

The heater does not operate.

Wiring diagram: 

EyeSight system Ref. to WIRING SYSTEM>EYESIGHT SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK RELAY UNIT  .
   1. Remove the heater relay from sub fuse box. Ref. to EYESIGHT>RELAY AND FUSE
   2. Using a tester, measure the resistance between the heater relay terminals.

      Terminal No.	Inspection conditions	Standard
      2 - 4	Always	144.6 - 176.8 Ω
      1 - 3	Always	1 MΩ or more
      1 - 3	Apply 12 V between terminals 2 - 4.	Less than 1 Ω

   Is the check result OK?

   Yes  : Go to  2.

   No  : Replace the relay. Ref. to EYESIGHT>RELAY AND FUSE

   And then, Go to  2.

2. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the connector from the stereo camera.
   2. Disconnect the connector from the heater.
   3. Using a tester, measure the resistance between the stereo camera connector and heater relay connector, and between the heater relay connector and chassis ground.

      Connector & terminal 

      (Rf21) No. 5 - Heater relay connector No. 2:

      Heater relay connector No. 4 - Chassis ground:

   Is the resistance less than 1 Ω?

   Yes  : Go to  3.

   No  : Repair or replace the harness.

   And then, Go to  3.

3. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Using a tester, measure the voltage between stereo camera connector and chassis ground.

   Connector & terminal 

   (Rf21) No. 5 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  4.

   No  : Repair or replace the harness.

   And then, Go to  4.

4. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY)  .

   Using a tester, measure the voltage between stereo camera connector and chassis ground.

   Connector & terminal 

   (Rf21) No. 5 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes  : Go to  5.

   No  : Repair or replace the harness.

   And then, Go to  5.

5. CHECK DTC  .
   1. Connect the disconnected connectors.
   2. Using the Subaru Select Monitor, perform the clear memory of [EyeSight]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
   3. Perform the heater heating test. Ref. to EYESIGHT>LENS HOOD>INSPECTION>HEATER HEATING AND COOLING FAN DRIVE TEST
   4. Read the DTC of [EyeSight] using the Subaru Select Monitor. Ref. to EYESIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC B28C6 displayed? (Current code)

   Yes  : Replace the stereo camera. Ref. to EYESIGHT>STEREO CAMERA

   And then, Go to  3.

   No  : Currently, it is normal. Finish the diagnosis.