DTC B28C5: Heat Generation Of Heater

DTC detecting condition:

When the stereo camera detected heater heating 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.

CAUTION:

Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to EYESIGHT (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

CHECK FUSE .
1. Turn the ignition switch to OFF.
2. Check fuse No. 32 in the fuse & relay box. Ref. to WIRING SYSTEM>EYESIGHT SYSTEM>WIRING DIAGRAM
Is the fuse OK?

Yes : Go to 2.

No : Replace the defective fuse. When the replaced fuse blows out easily, check the short circuit in harness.

CHECK RELAY UNIT .

Remove the heater relay from sub fuse box. Ref. to EYESIGHT>RELAY AND FUSE

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 3.

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

And then, Go to 3.

CHECK HEATER UNIT .
1. Disconnect the connector from the heater.
2. Check the heater. Ref. to EYESIGHT>LENS HOOD>INSPECTION
Is the check result OK?

Yes : Go to 4.

No : Replace the heater. Ref. to EYESIGHT>LENS HOOD

And then, Go to 4.
CHECK HARNESS (POWER SUPPLY CIRCUIT) .
Using a tester, measure the voltage between the heater relay connector and chassis ground.

Connector & terminal

Heater relay connector No. 1 - Chassis ground:

Is the voltage 9 - 16 V?

Yes : Go to 5.

No : Check the power supply system circuit, and if any fault is found, repair or replace the defective parts.

And then, Go to 5.
CHECK HARNESS (OPEN CIRCUIT) .
1. Disconnect the connector from the stereo camera.
2. Using a tester, measure the resistance between the stereo camera connector and heater connector and heater relay connector, between heater connector and heater relay connector, and between heater connector and heater relay connector and chassis ground.
  Connector & terminal
  
  (Rf21) No. 12 - (Rf47) No. 4:
  
  (Rf21) No. 24 - (Rf47) No. 5:
  
  (Rf21) No. 5 - Heater relay connector No. 2:
  
  (Rf47) No. 1 - Heater relay connector No. 3:
  
  (Rf47) No. 2 - Chassis ground:
  
  Heater relay connector No. 4 - Chassis ground:
Is the resistance less than 1 Ω?

Yes : Go to 6.

No : Repair or replace the harness.

And then, Go to 6.
CHECK HARNESS (GROUND SHORT CIRCUIT) .
Using a tester, measure the resistance between the stereo camera connector and heater connector and chassis ground.

Connector & terminal

(Rf21) No. 5 - Chassis ground:

(Rf47) No. 1 - Chassis ground:

(Rf47) No. 4 - Chassis ground:

(Rf47) No. 5 - Chassis ground:

Is the resistance 1 MΩ or more?

Yes : Go to 7.

No : Repair or replace the harness.

And then, Go to 7.
CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY) .
Using a tester, measure the voltage between the stereo camera connector and heater connector and chassis ground.

Connector & terminal

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

(Rf47) No. 1 (+) - Chassis ground (-):

(Rf47) No. 4 (+) - Chassis ground (-):

(Rf47) No. 5 (+) - Chassis ground (-):

Is the voltage less than 1 V?

Yes : Go to 8.

No : Repair or replace the harness.

And then, Go to 8.
CHECK HEATER OPERATION .
1. Connect the disconnected connectors.
2. Start the engine.
3. Using the Subaru Select Monitor, perform the clear memory of [EyeSight]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
4. Perform the heater heating test. Ref. to EYESIGHT>LENS HOOD>INSPECTION>HEATER HEATING AND COOLING FAN DRIVE TEST
5. Check if the heater is heated.
When both of the left and right are heated, go to A.

When both of the left and right are not heated, go to B.

When only one side is heated, go to C.
1. Currently, it is normal. Finish the diagnosis.
2. Replace the stereo camera. Ref. to EYESIGHT>STEREO CAMERA
3. Replace the heater. Ref. to EYESIGHT>LENS HOOD