Communication For Initializing Impossible

Detecting condition: 

• Defective harness connector
• Defective power steering control module

Trouble symptom: 

• Communication is impossible between the power steering control module and Subaru Select Monitor.
• After starting the engine, the STEERING warning light does not illuminate but steering effort is heavy.

Wiring diagram: 

Electric power steering system Ref. to WIRING SYSTEM>ELECTRIC POWER STEERING SYSTEM .

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 power steering 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.

3. CHECK BATTERY TERMINAL  .

   Is there poor contact at battery terminal?

   Yes: Replace or tighten the battery terminal.

   No: Go to  4.

4. CHECK POWER STEERING CONTROL MODULE CONNECTOR INSTALLATION  .

   Turn the ignition switch to OFF.

   Is the power steering control module connector inserted into the power steering control module until the clamp locks?

   Yes: Go to  5.

   No: Insert the power steering control module connector into the power steering control module.

5. CHECK LAN SYSTEM  .

   Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

   Is there any fault in LAN system?

   Yes: Perform the diagnosis according to DTC for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .

   No: Go to  6.

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

   Is «Select Function» displayed?

   Yes: Check DTC of electric power steering system. Ref. POWER ASSISTED SYSTEM (POWER STEERING) (DIAGNOSTICS)>Read 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 power steering control module connector and chassis ground.

      Connector & terminal

      (B204) No. 3 (+) - Chassis ground (-):

      (B206) No. 2 (+) - Chassis ground (-):

   Is the voltage 10 - 15 V?

   Yes: Go to  9.

   No: Repair the open circuit in the harness between the power steering control module and the battery.

9. CHECK HARNESS CONNECTOR BETWEEN POWER STEERING CONTROL MODULE AND CHASSIS GROUND  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the power steering control module connector.
   3. Measure the resistance of harness between power steering control module connector and chassis ground.

      Connector & terminal

      (B206) No. 1 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes: Go to  10.

   No: Repair the open circuit of the power steering control module ground circuit and the poor contact of connector.

10. CHECK POOR CONTACT OF CONNECTOR  .

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

    Yes: Repair the connector.

    No: Replace the steering gearbox. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>ELECTRIC POWER STEERING GEARBOX .