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HOMESERVICE MANUALSFORD2005TAURUS SEL, 4D SEDANREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1652 (ENGINE CONTROLS - PINPOINT TESTS - (HYBRID) - FAULT CODE INDEX, PINPOINT TESTS A - DN)PINPOINT TEST BA: POWER SUSTAIN RELAY (PSR)TEST PROCEDURE
2005 Ford Taurus SEL, 4D Sedan

Test Procedure

2005 Ford Taurus SEL, 4D SedanSECTION Test Procedure
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
  1. BA1 DTC P0685: DETERMINE THE DTC BEING DIAGNOSED 

    Is DTC P0685 present in the KOEO or KOER self-test? 

    Yes No
    GO to  BA2. GO to  BA7.
  2. BA2 KOEO AND KOER DTC P0685: CHECK THE B+ VOLTAGE TO PSR 
    • PSR connector disconnected.
    • Key ON, engine OFF.
    • Measure the voltage between:
      ( + ) PSR Connector, Harness Side ( - )
      B+ (coil) - Pin 1 Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    Key in OFF position.
    GO to  BA3.    		 REPAIR the open circuit.
  3. BA3 CHECK THE PSR RELAY 

    Is the PSR relay OK? 

    Yes No
    GO to  BA4. INSTALL a new PSR.
  4. BA4 CHECK THE PSR CIRCUIT FOR A SHORT TO POWER IN THE HARNESS 
    • PCM connector disconnected.
    • Key ON, engine OFF.
    • Measure the voltage between:
      ( + ) PSR Connector, Harness Side ( - )
      PSR - Pin 2 (86) Ground

    Is the voltage less than 1 V? 

    Yes No
    Key in OFF position.
    GO to  BA5.    		 REPAIR the short circuit.
  5. BA5 CHECK THE PSR CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PSR Connector, Harness Side ( - )
      PSR - Pin 2 (86) Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  BA6. REPAIR the short circuit.
  6. BA6 CHECK THE PSR CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PSR Connector, Harness Side ( - ) PCM Connector, Harness Side
      PSR - Pin 2 (86) PSR - Pin B27

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  BA9. REPAIR the open circuit.
  7. BA7 CONTINUOUS MEMORY DTC P0685: CHECK FOR AN INTERMITTENT SHORT TO GROUND IN THE PSR CIRCUIT 
    • PCM connector disconnected.
    • Connect a non-powered test lamp between:
      ( + ) Vehicle Battery ( - ) PCM Connector, Harness Side
      Positive terminal PSR - Pin B27
    • Key ON, engine OFF.
    • Observe the test lamp for an indication of a fault while completing the following. (Note that the lamp illuminates when a fault is detected).
      • Shake, wiggle, and bend the PSR circuit(s).
      • Lightly tap on the PSR to simulate road shock.

    Is a fault indicated? 

    Yes No
    Key in OFF position.
    ISOLATE the fault and REPAIR as necessary.
    CLEAR the DTCs. REPEAT the self-test.    		 Key in OFF position.
    GO to  BA8.
  8. BA8 CHECK FOR AN INTERMITTENT OPEN IN THE PSR CIRCUIT 
    • PSR connector disconnected.
    • Measure the resistance between:
      ( + ) PSR Connector, Harness Side ( - ) PCM Connector, Harness Side
      PSR - Pin 2 (86) PSR - Pin B27
    • Observe the DMM for an indication of a fault while completing the following. (Note that resistance changes suddenly when a fault is detected).
      • Shake, wiggle, and bend the PSR circuit.
      • Lightly tap on the PSR to simulate road shock.

    Is a fault indicated? 

    Yes No
    Key in OFF position. Key in OFF position.
    ISOLATE the fault and REPAIR as necessary. Unable to duplicate or identify the fault at this time.
    CLEAR the DTCs. REPEAT the self-test. GO to Pinpoint Test Z .
  9. BA9 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins.
      • corrosion.
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test and verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.