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Home >> Mercury >> 2007 >> Montego Base, AWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Test DK: Accelerator Pedal Position (App) Sensor Through Pinpoint Test DW: Heated Oxygen Sensor (Ho2S) - (Except Diesel & Hybrid) >> PINPOINT TEST DU: Intake Air Temperature 2 (IAT2) Sensor >> Test Procedure

Test Procedure

  1. DU1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Are DTCs P0097, P0098, P0127, P1114, or P1115 present? 
    Yes No
    For DTCs P0097 or P1114, GO to  DU4.
    For DTCs P0098 or P1115, GO to  DU2.
    For DTC P0127, GO to  DU6.    		 For all others, GO toDIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. DU2 CHECK FOR AN OPPOSITE SIGNAL TO THE PCM 
    • The DTC indicates the sensor signal is greater than the self-test maximum.
    • IAT2 Sensor connector disconnected.
    • Key ON, engine OFF.
    • Connect a 5 amp fused jumper wire between the following:
      Point A IAT2 Sensor Connector, Harness Side Point B IAT2 Sensor Connector, Harness Side
      IAT2 - Pin 1 SIGRTN - Pin 2
    • Access the PCM and monitor the IAT2 PID.
    • Is the voltage less than 0.2 V? 
    Yes No
    INSTALL a new IAT2 sensor. REFER to the appropriate ELECTRONIC ENGINE CONTROLS article. CLEAR the DTCs. REPEAT the self-test. GO to  DU3.
  3. DU3 CHECK THE SENSOR SIGNAL FOR A SHORT TO VREF 
    • Key in OFF position.
    • Remove the jumper wire(s).
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      IAT2 VREF
    • Is the resistance greater than 10K ohms? 
    Yes No
    GO to  DU10. REPAIR the short circuit to VREF. CLEAR the DTCs. REPEAT the self-test.
  4. DU4 DTC P1114: SIMULATE AN OPPOSITE SIGNAL TO THE PCM 
    • The DTC indicates the sensor signal is less than the self-test minimum.
    • IAT2 Sensor connector disconnected.
    • Key ON, engine OFF.
    • Access the PCM and monitor the IAT2 PID.
    • Is the voltage greater than 4.2 V? 
    Yes No
    INSTALL a new IAT2 sensor. REFER to the appropriate ELECTRONIC ENGINE CONTROLS article. CLEAR the DTCs. REPEAT the self-test. GO to  DU5.
  5. DU5 CHECK THE SENSOR SIGNAL FOR A SHORT TO GROUND 
    • Key in OFF position.
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      IAT2 SIGRTN
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) 12 Volt Vehicle Battery
      IAT2 Negative terminal
    • Is the resistance greater than 10K ohms? 
    Yes No
    GO to  DU10. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.
  6. DU6 DTC P0127: CHECK CHARGE AIR COOLER PUMP (CAC) OPERATION 
    Yes No
    GO to  DU7. DIAGNOSE the charge air cooler (CAC) pump.
    GO to KP9 .
  7. DU7 CHECK THE CHARGE AIR COOLER (CAC) SYSTEM 
    • Check the CAC system for low fluid level, cracked, blocked or misrouted coolant lines, cracked or blocked heat exchanger.
    • Is a concern present? 
    Yes No
    REFER to the SUPERCHARGER COOLING article. REPAIR as necessary.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  DU8.
  8. DU8 SIMULATE THE HIGH IAT2 SIGNAL TO THE PCM 
    • Key ON, engine OFF.
    • Access the PCM and monitor the IAT2 PID.
    • Observe the PID while disconnecting the IAT2 sensor.
    • Is the voltage greater than 4.2 V? 
    Yes No
    GO to  DU9. GO to  DU10.
  9. DU9 SIMULATE THE LOW IAT2 SIGNAL TO THE PCM 
    • Key in OFF position.
    • IAT2 Sensor connector disconnected.
    • Connect a 5 amp fused jumper wire between the following:
      Point A IAT2 Sensor Connector, Harness Side Point B IAT2 Sensor Connector, Harness Side
      IAT2 - Pin 1 SIGRTN - Pin 2
    • Key ON, engine OFF.
    • Access the PCM and monitor the IAT2 PID.
    • Is the voltage less than 0.2 V? 
    Yes No
    CONNECT the sensor and GO to the REFERENCE VALUES article, Reference Values. COMPARE the IAT2 PID to reference values under different road test conditions. If the sensor is not in range, INSTALL a new IAT2 sensor. REFER to the appropriate ELECTRONIC ENGINE CONTROLS article.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  DU10.
  10. DU10 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 toFLASH 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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