Body Integrated Unit Power Supply And Ground Circuit

NOTE: For the DC power supply circuit, refer to "WIRING DIAGRAMS". Ref. to WIRING SYSTEM>POWER SUPPLY CIRCUIT .

Courtesy of SUBARU OF AMERICA, INC.

CHECK DTC OF BODY INTEGRATED UNIT.
Check DTC of body integrated unit. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .

Is the DTC of power line displayed on body integrated unit?

Yes : Repair or replace it according to the DTC.

No : Go to 2.
CHECK CURRENT DATA.
Check the current data [BATT voltage (control)] display of body integrated unit. Ref. to BODY CONTROL (DIAGNOSTICS)>DATA MONITOR>OPERATION .

Is the display 10 - 15 V?

Yes : Go to 4.

No : Go to 3.
CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND BATTERY.
1. Turn the ignition switch to ON.
2. Measure the voltage between body integrated unit and chassis ground.
Connector and terminal

(B281) No. 7 (+) - Chassis ground (-):

(B287) No. 4 (+) - Chassis ground (-):

Is the voltage 9 - 16 V?

Yes : Go to 4.

No : Check harness for open circuit between the body integrated unit and the battery or a blown fuse.
CHECK BODY INTEGRATED UNIT IGN POWER SUPPLY CIRCUIT.
1. Turn the ignition switch to ON.
2. Measure the voltage between F/B fuse No. 5 and chassis ground.
Connector and terminal

F/B fuse No. 5 (+) - Chassis ground (-):

Is the display 10 V or more?

Yes : Go to 5.

No : Repair the open circuit of the harness between body integrated unit and ignition switch.
CHECK BODY INTEGRATED UNIT AND ACC VOLTAGE SUPPLY CIRCUIT.
1. Turn the ignition switch to ACC.
2. Measure the voltage between F/B fuse No. 9 and chassis ground.
Connector and terminal

F/B fuse No. 9 (+) - Chassis ground (-):

Is the display 10 V or more?

Yes : Go to 6.

No : Repair the open circuit of the harness between body integrated unit and ignition switch.
CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND CHASSIS GROUND.
1. Turn the ignition switch to OFF.
2. Measure the harness resistance between the body integrated unit and chassis ground.
Connector and terminal

(i84) No. 4 - Chassis ground:

(B287) No. 1 - Chassis ground:

Is the resistance less than 1 Ω?

Yes : Go to 7.

No : Repair the open circuit of harness between the body integrated unit and chassis ground.
CHECK FOR POOR CONTACT.
Is there poor contact of connector?

Yes : Repair the poor contact.

No : End.