DTC U1131: Lost Communication With Power Steering Control Module Ch-Bus

DTC detecting condition: 

No:  data is received from power steering Control Module.

Trouble symptom: 

• Cooperation control of EyeSight with power steering Control Module does not operate properly.
• When DTC U1131 is generated, it is possible that power steering Control Module is malfunctioning.

Cooperation control with body integrated unit does not operate properly.

1. CHECK CAN COMMUNICATION HARNESS 

   Perform the basic diagnostic procedure to check for fault in CAN communication harness. Ref. to LAN SYSTEM (DIAGNOSTICS)>Basic Diagnostic Procedure

   Was the basic diagnostic procedure performed up to step 7?

   Yes:  Go to 2

   No:  Perform the basic diagnostic procedure. Ref. to LAN SYSTEM (DIAGNOSTICS)>Basic Diagnostic Procedure

2. CHECK DTC (OTHER THAN U-CODE) 

   Check the displayed DTC.

   Is DTC other than U*** displayed? (Current code)

   Yes:  Perform the diagnosis for the displayed DTCs other than U-code.

   No:  Go to 3

3. CHECK DTC 

   Check the displayed DTC.

   Is DTC U1131 displayed? (Current code)

   Yes:  Go to 4

   No:  Go to 6

4. CHECK DTC 
   1. Check CAN communication circuit. Ref. to LAN SYSTEM (DIAGNOSTICS)>CAN Communication Circuit Check
   2. Turn the ignition switch to ON.
   3. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)

   Is DTC U1131 displayed? (Current code)

   Yes:  Go to 5

   No:  Go to 6

5. CHECK DTC 

   Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)

   Is DTC U1131 detected in central gateway Control Module? (Current code)

   Yes:  Replace the power steering Control Module. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>Power Steering Control Module

   No:  Replace the module that the DTC has been detected.

6. CHECK HARNESS 
   1. Shake the harness, and check for poor contact.
   2. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)

   Is DTC U1131 displayed? (Current code)

   Yes:  Repair the poor contact of harness, or replace the harness.

   No:  Go to 7

7. CHECK CONNECTOR 

   Check the connector used for high speed CAN for poor contact.

   Is there poor contact of connector?

   Yes:  Repair the connector that has poor contact, or replace harness.

   No:  It is possible that temporary poor communication occurs. Delete the DTC.