Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

Detecting condition: 

Defective harness connector

Trouble symptom: 

Communication is impossible between the steering angle sensor and Subaru Select Monitor.

Wiring diagram: 

Vehicle dynamics control system Ref. to WIRING SYSTEM>VEHICLE DYNAMICS CONTROL SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK IGNITION SWITCH  .

   Is the ignition switch ON?

   Yes:  Go to  2.

   No:  Turn the ignition switch to ON, and select the [Steering Angle Sensor] using the Subaru Select Monitor.

2. CHECK BATTERY  .
   1. Turn the ignition switch to OFF.
   2. Measure the battery voltage.

   Is the voltage 11 V or more?

   Yes:  Go to  3.

   No:  Charge or replace the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY>INSPECTION . Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>BATTERY .

3. CHECK BATTERY TERMINAL  .

   Is there poor contact at battery terminal?

   Yes:  Replace or tighten the battery terminal.

   No:  Go to  4.

4. CHECK INSTALLATION OF STEERING ANGLE SENSOR CONNECTOR  .

   Turn the ignition switch to OFF.

   Is the steering angle sensor connector inserted into the steering angle sensor until the clamp locks?

   Yes:  Go to  5.

   No:  Insert the steering angle sensor connector into the steering angle sensor.

5. CHECK LAN SYSTEM  .

   Check the LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

   Is the check result OK?

   Yes:  Go to  6.

   No:  Perform the diagnosis for LAN system.

6. CHECK SUBARU SELECT MONITOR COMMUNICATION  .
   1. Turn the ignition switch to ON.
   2. Check whether communication to steering angle sensor system can be executed normally.

   Is the [Select Function] screen displayed?

   Yes:  Check the DTC of the steering angle sensor system. Ref. to STEERING ANGLE SENSOR>DIAGNOSTIC TROUBLE CODE (DTC) .

   No:  Go to  7.

7. CHECK SUBARU SELECT MONITOR COMMUNICATION  .

   Connect the Subaru Select Monitor to another vehicle to check whether the communication for initializing can be executed normally.

   Does the Subaru Select Monitor communicate normally?

   Yes:  Go to  8.

   No:  Repair or replace the Subaru Select Monitor.

8. CHECK POWER SUPPLY CIRCUIT  .
   1. Turn the ignition switch to ON. (Engine OFF)
   2. Measure the ignition power supply voltage between the steering angle sensor connector and chassis ground.

      Connector & terminal 

      (i151) No. 4 (+) - Chassis ground (-):

   Is the voltage 10 - 15 V?

   Yes:  Go to  9.

   No:  Repair the open circuit of harness between the steering angle sensor and battery.

9. CHECK HARNESS CONNECTOR BETWEEN STEERING ANGLE SENSOR AND CHASSIS GROUND  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from steering angle sensor.
   3. Measure the resistance of harness between the steering angle sensor connector and chassis ground.

      Connector & terminal 

      (i151) No. 1 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  10.

   No:  Repair the open circuit of the steering angle sensor ground circuit and poor contact of connector.

10. CHECK POOR CONTACT OF CONNECTOR  .

    Is there poor contact of steering angle sensor power supply, ground circuit and data link connector?

    Yes:  Repair the connector.

    No:  Replace the steering angle sensor. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>STEERING ANGLE SENSOR .