PSCM Circuit Information

Refer to the Power Steering Controls wiring diagrams for schematic and connector information.

Refer to Steering GSB for additional connector and wiring inspection tips.

1. A1: CHECK PSCM COMMUNICATION WITH THE DIAGNOSTIC SCAN TOOL 
   • Start the vehicle.
     • Make sure the engine ready indicator is illuminated for hybrid vehicles.
   • Retrieve the continuous memory DTCs.
   • Does the diagnostic scan tool communicate with the PSCM and retrieve DTCs? 

     Yes	No
     Go to  A2.	Go to  A3.

2. A2: CHECK ALL MODULES FOR DTC U0131:XX 
   • Review the DTCs retrieved in the previous step.
   • Is DTC U0131:xx present in any module? 

     Yes	No
     Go to  A3.	If DTC U0131:XX is not present in any module, DISCONTINUE this test.

3. A3: CHECK THE VEHICLE BATTERY AND CHARGING SYSTEM VOLTAGE 
   • Ignition ON, engine OFF.
   • Refer to the Charging System General Information article and carry out Pinpoint Test A: Battery Condition Test (battery state of charge).
   • Did the battery pass the condition test (battery state of charge)? 

     Yes	No
     Go to  A4.	INSTALL a new 12-volt battery. REFER to the Battery, Mounting and Cables article.

4. A4: CHECK THE PSCM BATTERY AND IGNITION VOLTAGE 
   • Ignition OFF.
5. A5: CHECK THE PSCM GROUND CIRCUIT FOR AN OPEN 
   • Ignition OFF.
   • Disconnect the battery negative cable. Refer to the General Procedure, Battery Disconnect in the Battery, Mounting and Cables article.
   • Measure the resistance between:
6. A6: CHECK THE PSCM HS-CAN CIRCUITS FOR AN OPEN 
   • GWM connector disconnected. (C2431)
   • Measure the resistance between:
7. A7: VERIFY ALL PSCM WIRING CONNECTIONS 
   • Ignition OFF.
   • Disconnect all PSCM wiring harness in-line electrical connectors. Refer to the Power Steering Controls wiring diagrams for connector information. Refer to the PSCM Connection GSB for additional connection checks.
   • Using a good light source, inspect all PSCM and related in-line electrical connectors for:
     • corrosion - install a new connector or terminal and clean the module pins.
     • damaged or bent pins - install new terminals or pins.
     • pushed-out pins - install new pins as necessary.
     • spread terminals - install new terminals as necessary.
8. A8: CHECK FOR CORRECT PSCM POWER AND GROUND JOINT OPERATION 
   • Ignition OFF.
   • Disconnect and inspect the PSCM ground joint connection, clean or repair as necessary. Refer to the Power Steering Controls wiring diagrams for ground joint information.
9. A9: CHECK FOR INTERMITTENT PSCM WIRING HARNESS POWER AND GROUND CIRCUIT OPERATION 
   • Start the vehicle.
     • Make sure the engine ready indicator is illuminated for hybrid vehicles.
   • Make sure the front wheels are on the ground and the vehicle is not being supported by other means.
     • Make sure the front tires are clean and dry.
     • Make sure the ground under the front tires is clean and dry.
   • Take the following measurement while turning the steering wheel back and forth, lock to lock, continuously at 1 revolution per second.
   • Measure the voltage between:

     (+) 12 Volt Vehicle Battery	(-) 12 Volt Vehicle Battery
     Positive terminal	Negative terminal

   • Record the measured battery voltage.
   • View the following PID while turning the steering wheel back and forth, lock to lock, continuously at 1 revolution per second.
   • Access the PSCM and monitor the MOD_SUP_V (VOLT) PID.
   • Compare the measured battery voltage with the PID display.
     NOTE: If the scan tool cannot display the PID reading due to no communication with the PSCM, select the No Result/Action.
   • Do the measured battery voltage and the PID display differ by more than 1.5 volts? 

     Yes	No
     INSTALL a new PSCM wiring harness. Go to  A10.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded PSCM electrical connector or a wiring harness in-line electrical connector and was repaired during this procedure.

10. A10: VERIFY PSCM OPERATION 
    • Start the vehicle.
      • Make sure the engine ready indicator is illuminated for hybrid vehicles.
    • Make sure the front wheels are on the ground and the vehicle is not being supported by other means.
      • Make sure the front tires are clean and dry.
      • Make sure the ground under the front tires is clean and dry.
    • Take the following measurement while turning the steering wheel back and forth, lock to lock, continuously at 1 revolution per second.
    • Measure the voltage between:

      (+) 12 Volt Vehicle Battery	(-) 12 Volt Vehicle Battery
      Positive terminal	Negative terminal

    • Record the measured battery voltage.
    • View the following PID while turning the steering wheel back and forth, lock to lock, continuously at 1 revolution per second.
    • Access the PSCM and monitor the MOD_SUP_V (VOLT) PID.
    • Compare the measured battery voltage with the PID display.
    • Do the measured battery voltage and the PID display differ by more than 1.5 volts? 

      Yes	No
      INSTALL a new PSCM wiring harness and CARRY OUT this step again. Go to  A11.	The repair is complete.

11. A11: RETRIEVE DTCS FROM ALL MODULES 
    • Using a diagnostic scan tool, clear DTC U0131:xx from the reporting module.
    • Ignition OFF.
    • Start the vehicle.
      • Make sure the engine ready indicator is illuminated for hybrid vehicles.
    • Operate the system.
    • Retrieve the continuous memory DTCs.
    • Is DTC U0131:xx present in any module? 

      Yes	No
      Go to  A12.	The condition to set the DTC is not present and may have been caused by a loose, damaged or corroded electrical connector. The repair is complete, no further action is required.

12. A12: CHECK FOR APPLICABLE SERVICE ARTICLES 
    • Ignition OFF.
    • Check OASIS for any applicable TSBs, GSBs, SSMs or FSAs.
    • Does a service article exist for DTC U0131 Lost Communication With The PSCM or PSCM no communication with the diagnostic scan tool? 

      Yes	No
      DISCONTINUE this test and FOLLOW the service article instructions.	INSTALL a new EPAS gear. REFER to the Power Steering article. ORDER a replacement EPAS gear and INCLUDE the RVC on the order form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.