Diagnostic Procedure

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK BRAKE LIGHT. Turn the ignition switch to ON.	Does the brake light go off when the brake pedal is not depressed?	Go to step 5 .	Go to step 2 .
2 CHECK HARNESS. Turn the ignition switch to OFF. Disconnect the brake light relay connector. Turn the ignition switch to ON. Measure the voltage between the brake light relay connector and chassis ground. Connector & terminal Brake relay No. 1 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Repair or replace the harness.	Go to step 3 .
3 CHECK HARNESS. Measure the voltage between the brake light relay connector and chassis ground. Connector & terminal Brake relay No. 2 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 4 .	Replace the brake light relay. < Refer to REMOVAL , Brake Lamp Relay. >
4 CHECK HARNESS. Turn the ignition switch to OFF. Disconnect the connector from the stereo camera. Turn the ignition switch to ON. Measure the voltage between the brake light relay connector and chassis ground. Connector & terminal Brake relay No. 2 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Repair the harness.	Replace the stereo camera. < Refer to REMOVAL , Stereo Camera. >
5 CHECK BRAKE LIGHT RELAY. Turn the ignition switch to OFF. Disconnect the brake light relay connector. Check the brake light relay.	Is the brake light relay OK?	Go to step 6 .	Replace the brake light relay. < Refer to REMOVAL , Brake Lamp Relay. >
6 CHECK HARNESS. Disconnect the connector from the VDCCM&H/U. Measure the resistance between brake light relay and VDCCM&H/U harness connector. Connector & terminal Brake relay No. 1 - (B310) No. 3:	Is the resistance less than 10 Ω?	Go to step 7 .	Repair or replace the harness.
7 CHECK HARNESS. Disconnect the stop light & brake switch connector. Disconnect the connector of body integrated unit. Measure the resistance between stop light & brake switch and harness connector of body integrated unit. Connector & terminal (B65) No. 3 - (B280) No. 10:	Is the resistance less than 10 Ω?	Go to step 8 .	Check harness between stop light switch and body integrated unit.
8 CHECK CONNECTOR. Check the connectors for brake light relay, stereo camera, VDCCM&H/U and body integrated unit.	Is the connector normal?	Go to step 9 .	Repair or replace the connector.
9 CHECK HARNESS. Disconnect the brake light relay connector. Measure the voltage between the brake light relay connector and chassis ground. Connector & terminal Brake relay No. 3 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 10 .	Check the power supply system harness.
10 CHECK HARNESS. Measure the resistance between the brake light relay harness connector and chassis ground. Connector & terminal Brake relay No. 4 - Chassis ground:	Is the resistance less than 10 Ω?	Go to step 11 .	Check the ground system harness.
11 CHECK HARNESS. Disconnect the stereo camera. Disconnect the brake light relay connector. Measure the resistance between the harness connectors of stereo camera and brake light relay. Connector & terminal (R137) No. 4 - Brake relay No. 2:	Is the resistance less than 10 Ω?	Go to step 12 .	Repair or replace the connector.
12 CHECK HARNESS. Measure the resistance between the brake light relay harness connector and chassis ground. Connector & terminal Brake relay No. 1 - Chassis ground:	Is the resistance 1 MΩ or more?	Check the brake light bulb and harness.	Go to step 13 .
13 CHECK HARNESS. Measure the resistance between the harness connectors of stop light & brake switch and brake light relay. Connector & terminal (B65) No. 3 - Brake relay No. 5:	Is the resistance less than 10 Ω?	Go to step 14 .	Check the harness.
14 CHECK STEREO CAMERA. Connect all connectors securely. Turn the ignition switch to ON. Connect the Subaru Select Monitor. Read the DTC.	Is another DTC displayed?	Perform the diagnosis according to DTC.	Go to step 15 .
15 CHECK STEREO CAMERA. Clear the memory. Start the engine. After 5 seconds of the engine start, depress and hold the brake pedal for 3 seconds or more. Operate the adaptive cruise control with preceding vehicle adaptive function in all speed ranges, apply brake by deceleration control. Read the DTC.	Is DTC B2817 displayed?	Replace the stereo camera. < Refer to REMOVAL , Stereo Camera. >	Temporary poor contact occurs.