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HOMESERVICE MANUALSFORD2004MUSTANG BASE, 2D COUPE, 3.9 6, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 2542 (ENGINE CONTROLS - PINPOINT TEST A: NO START THROUGH PINPOINT TEST DK: ACCELERATOR PEDAL POSITION (APP) SENSOR - (EXCEPT DIESEL & HYBRID))PINPOINT TEST DA: INTAKE AIR TEMPERATURE (IAT) SENSORTEST PROCEDURE
2004 Ford Mustang Base, 2D Coupe, 3.9 6, Automatic

Test Procedure

2004 Ford Mustang Base, 2D Coupe, 3.9 6, AutomaticSECTION Test Procedure
WARNING: This page does not describe the selected car, but rather 22 other vehicles, including the 2011 Mercury Milan, 2011 Mercury Mariner, 2011 Mercury Grand Marquis, 2011 Lincoln Town Car, and 2011 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.
  1. DA1 PRELIMINARY DIAGNOSIS 

    Are DTCs P009A, P0111, P0112, P0113, P0114, or P1112 present? 

    Yes No
    For DTCs P009A, P0111, P0112, P0113, P0114 or P1112, GO to  DA2.
    For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .    		 For symptoms without DTCs, GO to  DA2.
  2. DA2 CHECK FOR AN OPEN IN THE HARNESS 
    NOTE: Only measure the circuits that apply to the vehicle being diagnosed. Refer to the appropriate Wiring Diagram for the MAF/IAT sensor to determine which circuits to measure.
    • Ignition OFF.
    • IAT Sensor connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) IAT Sensor Connector, Harness Side (-)
      SIGRTN Ground
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) IAT Sensor Connector, Harness Side (-) PCM Connector, Harness Side
      IAT IAT
      SIGRTN SIGRTN
      SIGRTN MAF RTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DA3. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  3. DA3 CHECK FOR A SHORT BETWEEN CIRCUITS IN THE HARNESS 
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) IAT Sensor Connector, Harness Side (-)
      IAT Ground
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) IAT Sensor Connector, Harness Side (-) IAT Sensor Connector, Harness Side
      IAT VPWR
      IAT MAF RTN
      IAT SIGRTN
      IAT MAF

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  DA4. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  4. DA4 CHECK FOR A SHORT TO VOLTAGE IN THE HARNESS 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      VOLTAGE REFERENCE CHART

      (+) IAT Sensor Connector, Harness Side (-)
      IAT Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to  DA5.
  5. DA5 INTERMITTENT CHECK 
    • Ignition OFF.
    • PCM connector connected.
    • IAT Sensor connector connected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the IAT (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 IAT sensor and wiggle the harness connector to simulate road shock.

    Does the IAT PID reading change? 

    Yes No
    REPAIR as necessary or INSTALL a new IAT sensor. REFER to the appropraite Electronic Engine Controls . RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.    		 GO to  DA6.
  6. DA6 INTAKE AIR TEMPERATURE (IAT) SENSOR AMBIENT AIR TEMPERATURE (AAT) 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 ON, engine OFF.
    • Access the PCM and monitor the IAT (TEMP) PID.
    • For Fiesta,
    • Access the PCM and monitor the OUTDR_TMP (TEMP) PID.
    • For all others,
    • Access the PCM and monitor the AAT (TEMP) PID.

    Are the temperature readings within 18°C (32.4°F) of each other? 

    Yes No
    GO to  DA7. INSTALL a new IAT sensor. REFER to the appropriate Electronic Engine Controls articles . RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  7. DA7 CHECK THE IAT CIRCUIT VOLTAGE CYCLING INTEGRITY 
    • Ignition OFF.
    • IAT Sensor connector disconnected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the IAT (VOLT) PID.
    • Record the IAT PID value.
    • Connect a 5 amp fused jumper wire between the following:
      CONNECTOR PINS REFERENCE CHART

      Point A IAT Sensor Connector, Harness Side Point B IAT Sensor Connector, Harness Side
      IAT SIGRTN
    • Record the IAT PID value.

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

    Yes No
    INSTALL a new IAT sensor. REFER to the appropriate Electronic Engine Controls article . RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.    		 GO to  DA8.
  8. DA8 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) , PROGRAMMING THE VID BLOCK FOR A REPLACEMENT PCM . 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.