Seat Heater Does Not Operate By Telematics

Trouble symptom: 

Operation of the seat heater by the telematics is attempted, but unsuccessful.

Trouble causes: 

• Seat ventilation Control Module failure
• A/C Control Module failure
• Seat ventilation circuit failure
• Seat heater circuit failure
• Center information display failure
• Cockpit control module failure
• Heater failure

Wiring diagram: 

Seat heater system. Refer to WIRING SYSTEM>Seat Heater System>WIRING DIAGRAM .

Seat ventilation system. Refer to WIRING SYSTEM>Seat Ventilation System>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the following DTCs using Subaru Select Monitor. Refer to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to COCKPIT CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
   • Ventilation Seat
   • Body Control
   • Air Conditioner
   • Cockpit Control
   • Telematics

   Are any DTCs displayed?

   Yes  : Perform the diagnosis for the displayed DTCs. Refer to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to COCKPIT CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Refer to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   No  : Go to  2.

2. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check malfunctions (terminal bends, connection status, etc.) of the seat ventilation Control Module connector (St41), A/C Control Module connectors (i107) (i108), seat connectors (L57) (R57), coupling connectors (B43) (L51) (R51), and heater connectors (St27) (St28).

   Is the check result OK?

   Yes  : Go to  3.

   No  : Repair the connector.

3. CHECK CAN COMMUNICATION LINE  .

   Inspect LAN system. Refer to LAN SYSTEM (DIAGNOSTICS)>Basic Diagnostic Procedure>PROCEDURE .

   Is the check result OK?

   Yes  : Go to  4.

   No  : Perform the inspection according to the diagnosis for LAN system. Refer to LAN SYSTEM (DIAGNOSTICS)>Basic Diagnostic Procedure>PROCEDURE .

4. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the driver's side seat connector (L57) and passenger's side seat connector (R57).
   2. Turn the ignition switch to ON.
   3. Using the tester, measure the voltage between terminals.

   Connector & terminal 

   Driver's side 

   (L57) No. 9 (+) - Chassis ground (-):

   Passenger's side 

   (R57) No. 9 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes  : Go to  5.

   No  : Repair or replace the open circuit of harness.

5. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the A/C Control Module connectors (i107) and (i108).
   3. Using the tester, measure the resistance between terminals.

   Connector & terminal 

   Driver's side 

   (L57) No. 10 - (i108) No. 7:

   (L57) No. 15 - (i108) No. 1:

   (L57) No. 16 - (i107) No. 15:

   Passenger's side 

   (R57) No. 10 - (i108) No. 7:

   (R57) No. 15 - (i108) No. 5:

   (R57) No. 16 - (i107) No. 14:

   Is the resistance less than 5 Ω?

   Yes  : Go to  6.

   No  : Repair or replace the open circuit of harness.

6. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the driver's side heater connector (St28) and passenger's side heater connector (St27).
   3. Using the tester, measure the resistance between terminals.

   Connector & terminal 

   Driver's side 

   (St28) No. 1 - (St2) No. 9:

   (St28) No. 2 - (St2) No. 15:

   (St28) No. 3 - (St2) No. 16:

   (St28) No. 4 - (St2) No. 10:

   Passenger's side 

   (St27) No. 1 - (St1) No. 9:

   (St27) No. 2 - (St1) No. 15:

   (St27) No. 3 - (St1) No. 16:

   (St27) No. 4 - (St1) No. 10:

   Is the resistance less than 5 Ω?

   Yes  : Go to  7.

   No  : Repair or replace the open circuit of harness.

7. CHECK CENTER INFORMATION DISPLAY  .
   1. Connect all connectors.
   2. Turn the ignition switch to ON.
   3. Start the engine.
   4. Touch the seat heater switch, and check if the display for seat heater operation mode changes.

   Does the display change?

   Yes  : Go to  8.

   No  : Refer to VENTILATION SEAT (DIAGNOSTICS)>Diagnostics with Phenomenon>INSPECTION>DISPLAY DOES NOT CHANGE ALONG WITH SEAT HEATER SWITCH OPERATION .

8. CHECK OPERATION MODE  .
   1. Touch the seat heater switch.
   2. Using the Subaru Select Monitor, check the following items in the [Data monitor] of [Ventilation Seat]. Refer to VENTILATION SEAT (DIAGNOSTICS)>Data Monitor .
   • Seat Heater Operation Steps(Driver's)
   • Seat Heater Operation Steps(Passenger's)

   Does the operation mode change?

   Yes  : Go to  9.

   No  : Refer to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>SEAT HEATER LEVEL DOES NOT CHANGE (DISPLAY CHANGES, BUT OPERATION DOES NOT CHANGE) .

9. CHECK SEAT HEATER  .
   1. Start the engine.
   2. Activate the seat heater.
   3. After a predetermined period of time, check if the back rest and cushion are both heated.

   Are both the back rest side and cushion side operating?

   Yes  : Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

   No  : Refer to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>SEAT HEATER ON ONE SIDE (BACK REST SIDE OR CUSHION SIDE) DOES NOT OPERATE .