Diagnostic Procedure

WARNING: This page is about a different car, the 2013 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK DTC. Read the DTC of body integrated unit using Subaru Select Monitor.< Refer to OPERATION , Subaru Select Monitor. >	Is U1302 a current malfunction?	Go to step 2 .	Go to step 8 .
2 CHECK DTC. Turn the ignition switch to OFF. Disconnect all connectors (i84, i10, i88, i85 or i50) that are connected to low speed CAN communication line. Connect the disconnected connectors. Turn the ignition switch to ON. Read the DTC of body integrated unit using Subaru Select Monitor.	Is U1302 a current malfunction?	Go to step 3 .	Go to step 8 .
3 CHECK HARNESS. Turn the ignition switch to OFF. Disconnect all connectors (i84, i10, i88, i85 or i50) that are connected to low speed CAN communication line. Using the tester, check for open, short (power supply-output short, GND-output short) in the harness. Connector & terminal (i84) No. 1 - (i10) No. 27 (combination meter): (i84) No. 9 - (i10) No. 26 (combination meter): (i84) No. 1 - (i88) No. 20 (A/C): (i84) No. 9 - (i88) No. 19 (A/C): (i84) No. 1 - (i85) No. 12 (audio): (i84) No. 9 - (i85) No. 11 (audio): (i84) No. 1 - (i50) No. 18 (navigation): (i84) No. 9 - (i50) No. 6 (navigation):	Is harness normal?	Go to step 4 .	Repair or replace the harness.
4 CHECK HARNESS. Connect the disconnected connectors. Using the tester, measure the resistance between harness connector and chassis ground. Connector & terminal (i84) No. 1 - Chassis ground: (i84) No. 9 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 5 .	Go to step 7 .
5 CHECK HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between harness connector and chassis ground. Connector & terminal (i84) No. 1 (+) - Chassis ground (-): (i84) No. 9 (+) - Chassis ground (-):	Is the voltage less than 6 V?	Replace the body integrated unit.< Refer to REMOVAL , Body Integrated Unit. >	Go to step 6 .
6 CHECK HARNESS. With the tester connected, disconnect control module.	Is there any control module whose voltage has changed?	Replace the control module whose voltage has changed.	Repair or replace the short circuit of the harness.
7 CHECK HARNESS. With the tester connected, disconnect control module.	Is there any control module whose resistance has changed?	Replace the control module whose resistance has changed.	Repair or replace the short circuit of the harness.
8 CHECK HARNESS. Turn the ignition switch to OFF. Shake the harness used for low speed CAN communication circuit. Turn the ignition switch to ON. Read the DTC of body integrated unit using Subaru Select Monitor.	Is U1302 a current malfunction?	Repair or replace the open, short circuit of the harness.	Go to step 9 .
9 CHECK CONNECTOR. Turn the ignition switch to OFF. Disconnect all connectors (i84, i10, i88, i85 or i50) that are connected to low speed CAN communication line.	Is there poor contact of connector terminal?	Repair the connector terminal, or replace harness.	Temporary communication failure occurs.