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HOMESERVICE MANUALSFORD2005TAURUS SEL, 4D SEDANREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1484 (ENGINE CONTROLS - PINPOINT TESTS (HYBRID))PINPOINT TEST DN: MOTOR ELECTRONICS COOLANT TEMPERATURE (MECT) SENSORTEST 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 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
  1. DN1 DTCS P0A00, P0A01, P0A02, P0A03, P0A05 AND P0A7C: CHECK FOR SELF-TEST DTCS 

    Are DTCs P0A00, P0A01, P0A02, P0A03, P0A05, or P0A7C present during PCM or transaxle control module (TCM) self-test? 

    Yes No
    For DTCs P0A00 or P0A7C, GO to  DN2.
    For DTC P0A01, GO to  DN15.
    For KOEO and KOER DTC P0A02, GO to  DN10.
    For KOEO and KOER DTC P0A03, GO to  DN6.
    For continuous memory DTCs P0A02 or P0A03, GO to  DN12.
    For DTC P0A05, GO to PINPOINT TEST KT .    		 Unable to duplicate or identify the concern at this time.
    RETURN to SYMPTOM CHARTS for further direction.
  2. DN2 DTCS P0A00 AND P0A7C: VISUALLY INSPECT THE MOTOR ELECTRONICS COOLING SYSTEM 
    • Visually inspect the motor electronics cooling system for leaks, pinched hoses, restricted radiator air flow, correct coolant level, fan operation, and incorrect electrical connections.

    Is the motor electronics cooling system OK? 

    Yes No
    For DTC P0A7C, GO to  DN3.
    For all others, GO to  DN4.    		 REFER to the ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) , to diagnose the motor electronics cooling system overheating concern.
  3. DN3 P0A7C: CHECK FOR COOLANT FLOWING INTO THE DEGAS RESERVOIR 
    • Ignition ON, engine OFF.
    • Access the PCM and control the MECP (MODE) PID.
    • Run the MECS pump while observing the coolant flowing into the degas reservoir.
    • Command the MECS pump OFF.

    Did the coolant flow into the degas reservoir? 

    Yes No
    GO to  DN4. REFER to the PINPOINT TEST A: MECS COOLING PUMP FAULT Follow the pinpoint test as if there are no DTCs present. If the MECS cooling pump passed the pinpoint test, GO to DN4 in this pinpoint test.
  4. DN4 ROAD TEST THE VEHICLE AND MONITOR THE MECT_V PID 
    NOTE: Under normal operating conditions, the motor electronics coolant temperature should not exceed 65°C (150°F) and maintain a temperature of approximately 11°C (20°F) over ambient temperature during a steady cruise above 65 km/h (40mph).
    • Access the PCM and monitor the MECT_V (VOLT) PID.
    • Road test the vehicle by performing heavy accelerations and decelerations over a 15 minute period.
    • Refer to the RESISTANCE REFERENCE CHART  for voltage specifications.

    Does the MECT sensor operate in the normal temperature range? 

    Yes No
    GO to  DN12. GO to  DN5.
  5. DN5 CHECK THE RESISTANCE OF THE MECT SENSOR 
    NOTE: Refer to the RESISTANCE REFERENCE CHART  for temperature versus resistance specifications.
    • MECT Sensor connector disconnected.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) MECT Sensor Connector, Component Side (-) MECT Sensor Connector, Component Side
    MECT - Pin 1 SIGRTN - Pin 2

    Does the resistance of the MECT sensor match the actual motor electronics coolant system coolant temperature? 

    Yes No
    REFER to the AUTOMATIC TRANSAXLE COOLING (ECVT) (HYBRID) , to diagnose the motor electronics cooling system overheating concern. INSTALL a new MECT sensor. Clear the PCM DTCs. REPEAT the self-test.
  6. DN6 DTC P0A03: CHECK THE MECT CIRCUIT FOR A SHORT TO PWR IN THE HARNESS 
    • MECT Sensor connector disconnected.
    • PCM connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    VOLTAGE REFERENCE CHART

    (+) MECT Sensor Connector, Harness Side (-)
    MECT - Pin 1 Ground

    Is the voltage less than 5 V? 

    Yes No
    GO to  DN7. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test. CHECK MECT sensor for damage.
    GO to  DN7.
  7. DN7 CHECK THE RESISTANCE OF THE MECT SENSOR WITH THE ENGINE OFF 
    NOTE: Refer to the RESISTANCE REFERENCE CHART  for the resistance specifications.
    • Ignition OFF.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) MECT Sensor Connector, Component Side (-) MECT Sensor Connector, Component Side
    MECT - Pin 1 SIGRTN - Pin 2

    Is the resistance within specification? 

    Yes No
    GO to  DN8. INSTALL a new MECT sensor. Clear the PCM DTCs. REPEAT the self-test.
  8. DN8 CHECK THE SIGNAL AND SIGRTN CIRCUITS FOR AN OPEN IN THE HARNESS 
    • Ignition OFF.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) MECT Sensor Connector, Harness Side (-) PCM Connector, Harness Side
    MECT - Pin 1 MECT - Pin T29
    SIGRTN - Pin 2 SIGRTN - Pin T40

    Is each resistance less than 5 ohms? 

    Yes No
    GO to  DN9. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  9. DN9 CHECK THE SENSOR SIGNAL FOR A SHORT TO VREF 
    • Ignition OFF.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) PCM Connector, Harness Side
    MECT - Pin T29 VREF - Pin B66

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  DN18. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  10. DN10 DTC P0A02: SIMULATE AN OPPOSITE SIGNAL TO THE PCM 
    • MECT Sensor connector disconnected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the MECT_V (VOLT) PID.

    Is the voltage greater than 4.2 V? 

    Yes No
    INSTALL a new MECT sensor. Clear the PCM DTCs. REPEAT the self-test. GO to  DN11.
  11. DN11 CHECK THE SENSOR SIGNAL FOR A SHORT TO GROUND 
    • Ignition OFF.
    • PCM connector disconnected.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) MECT Sensor Connector, Harness Side (-) MECT Sensor Connector, Harness Side
      MECT - Pin 1 SIGRTN - Pin 2
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) Vehicle Battery
    MECT - Pin T29 Negative terminal

    Are the resistances greater than 10,000 ohms? 

    Yes No
    GO to  DN18. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  12. DN12 CONTINUOUS MEMORY DTCS P0A00, P0A02, P0A03 AND P0A7C: CHECK THE MECT SENSOR FOR AN INTERMITTENT CONCERN 
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the MECT_V (VOLT) PID.
    • While observing the PID, carry out the following:
      • tap on the sensor to simulate road shock
      • wiggle the sensor connector

      Does the MECT_V PID voltage indicate a concern in the MECT sensor? 

      Yes No
      DISCONNECT and INSPECT the connector.
      If OK, INSTALL a new MECT sensor.
      Clear the PCM DTCs. REPEAT the self-test.      		 GO to  DN13.
  13. DN13 CHECK THE MECT CIRCUIT FOR AN INTERMITTENT CONCERN 
    • Access the PCM and monitor the MECT_V (VOLT) PID.
    • While observing the PID, wiggle, shake, and bend small sections of the wiring harness working from the sensor to the PCM.

    Does the MECT_V PID voltage indicate a concern in the MECT circuit? 

    Yes No
    ISOLATE the concern and REPAIR as necessary.
    CARRY OUT the Comprehensive Component Monitor Drive Cycle. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .    		 GO to  DN14.
  14. DN14 CHECK THE PCM AND VEHICLE HARNESS CONNECTORS 
    • PCM connector disconnected.
    • MECT Sensor connector disconnected.

    Are the connectors and terminals OK? 

    Yes No
    Unable to duplicate or identify the concern at this time.
    GO to PINPOINT TEST Z .    		 REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.
  15. DN15 CHECK FOR THE PRESENCE OF PCM DTCS P0A00, P0A02, P0A03, P0A7C 
    NOTE: The TCM DTC P0A01 may be stored as a result of the MECT sensor or a corresponding circuit concern.

    The PCM DTCs P0A00, P0A02, P0A03, or P0A7C present along with a P0A05 indicate the MECT sensor or harness concern.

    Are any of the above listed DTCs present? 

    Yes No
    DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS . GO to  DN16.
  16. DN16 VERIFY THAT THE CONCERN IS PRESENT 
    NOTE: Clearing the TCM DTCs erases any TCM recorded freeze frame data. Record any TCM freeze frame information before proceeding any further. Refer to the scan tool instruction manual for freeze frame PID menu.
    • Clear and retrieve the TCM continuous DTCs.

    Is DTC P0A01 present? 

    Yes No
    GO to  DN17. Unable to duplicate or identify the concern at this time.
  17. DN17 CHECK THE TCM MECT PID 
    • Ignition ON, engine OFF.
    • Access the TCM and monitor the MECT (TEMP) PID.
    • Start the engine using the engine running diagnostic mode. Refer to DIAGNOSTIC MODES .
    • Turn on all optional electrical loads.
    • Idle the engine for 5 minutes with the load on and monitor the MECT PID.

    Does the MECT PID temperature increase by at least 1 degree? 

    Yes No
    INSTALL a new transaxle assembly. REFER to the ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) GO to  DN18.
  18. DN18 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.
    • 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.
RENDER: 1.0x

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