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Home >> Ford >> 2014 >> Fusion Energi Titanium >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Pinpoint Tests (Hybrid) >> Pinpoint Test FB: Ambient Air Temperature (AAT) >> Test Procedure

Test Procedure

  1. FB1 PRELIMINARY DIAGNOSIS 
    NOTE: Diagnose any circuit DTCs before range or performance DTCs.

    Is DTC P0072, P0073 or P0074 present? 

    Yes No
    GO to FB2  . For symptoms without DTCs, GO to FB2  .
    For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. FB2 CHECK FOR AN OPEN 
    • Ignition OFF.
    • PCM connector disconnected.
    • For C-MAX,
    • Right Exterior Rear View Mirror Assembly connector disconnected.
    • Measure the resistance between:
      (+) Right Exterior Rear View Mirror Assembly Connector, Harness Side (-) PCM Connector, Harness Side
      AAT - Pin 9 AAT - Pin B33
      SIGRTN - Pin 10 SIGRTN - Pin B45
    • For all others,
    • AAT Sensor connector disconnected.
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) PCM Connector, Harness Side
      AAT - Pin 1 AAT - Pin B33
      SIGRTN - Pin 2 SIGRTN - Pin B45

    Are the resistances less than 5 ohms? 

    Yes No
    GO to FB3  . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  3. FB3 CHECK FOR A SHORT TO GROUND 
    • For C-MAX,
    • Measure the resistance between:
      (+) Right Exterior Rear View Mirror Assembly Connector, Harness Side (-)
      AAT - Pin 9 Ground
    • For all others,
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-)
      AAT - Pin 1 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to FB4  . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  4. FB4 CHECK FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • For C-MAX,
    • Measure the voltage between:
      (+) Right Exterior Rear View Mirror Assembly Connector, Harness Side (-)
      AAT - Pin 9 Ground
    • For all others,
    • Measure the voltage between:
      (+) AAT Sensor Connector, Harness Side (-)
      AAT - Pin 1 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to FB5  .
  5. FB5 INTERMITTENT CHECK 
    • Ignition OFF.
    • PCM connector connected.
    • For C-MAX,
    • Right Exterior Rear View Mirror Assembly connector connected.
    • For all others,
    • AAT Sensor connector connected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT_V (VOLT) PID.
    • While observing the PID, wiggle, shake, and bend small sections of the wiring harness working from the sensor to the PCM.
    • Lightly tap on the AAT sensor and wiggle the harness connector to simulate road shock.

    Does the AAT PID reading change? 

    Yes No
    For C-MAX, REPAIR as necessary or INSTALL a new Right Exterior Rear View Mirror Assembly. REFER to the Rear View Mirrors article.
    For all others, REPAIR as necessary or INSTALL a new AAT sensor. REFER to the Climate Control article.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to FB6  .
  6. FB6 CHECK THE CIRCUIT VOLTAGE CYCLING INTEGRITY 
    • Ignition OFF.
    • For C-MAX,
    • Right Exterior Rear View Mirror Assembly connector disconnected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT_V (VOLT) PID.
    • Record the AAT PID value.
    • Connect a 5 amp fused jumper wire between the following:
      Point A Right Exterior Rear View Mirror Assembly Connector, Harness Side Point B Right Exterior Rear View Mirror Assembly Connector, Harness Side
      AAT - Pin 9 SIGRTN - Pin 10
    • Record the AAT PID value.
    • For all others,
    • AAT Sensor connector disconnected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT_V (VOLT) PID.
    • Record the AAT PID value.
    • Connect a 5 amp fused jumper wire between the following:
      Point A AAT Sensor Connector, Harness Side Point B AAT Sensor Connector, Harness Side
      AAT - Pin 1 SIGRTN - Pin 2
    • Record the AAT PID value.

    Does the AAT PID change from greater than 3.0 volts to less than 0.20 volt when the jumper is connected? 

    Yes No
    For C-MAX, INSTALL a new Right Exterior Rear View Mirror Assembly. REFER to the Rear View Mirrors article.
    For all others, INSTALL a new AAT sensor. REFER to the Climate Control article.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to FB7  .
  7. FB7 TEMPERATURE SENSOR CORRELATION 
    NOTE: Check temperature values while engine is at ambient temperature, cold soak the engine for a minimum of 8 hours while not in direct sun light, if necessary.
    • Ignition OFF.
    • For C-MAX,
    • Right Exterior Rear View Mirror Assembly connector connected.
    • For all others,
    • AAT Sensor connector connected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT (TEMP), CHT (TEMP) and IAT (TEMP) PIDs.

    Are the temperature readings within 17°C (30°F) of each other? 

    Yes No
    GO to FB8  . For C-MAX, INSTALL a new Right Exterior Rear View Mirror Assembly. REFER to the Rear View Mirrors article.
    For all others, INSTALL a new AAT sensor. REFER to the Climate Control article.
    Clear the PCM DTCs. REPEAT the self-test.
  8. FB8 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.
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