Chrysler Concorde/Intrepid/LHS/New Yorker/Vision 1993-1997

Intake Air Temperature (IAT) Sensor

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OPERATION



The Intake Air Temperature (IAT) sensor threads into the intake plenum and measures the air temperature. The IAT sensor provides an input to the Powertrain Control Module (PCM) on a circuit. From this circuit, the sensor draws a voltage from the PCM. The sensor is a variable resistor. As intake air temperature changes, the resistance in the sensor changes, causing a change in the current draw.

The PCM then provides a ground path for the intake air temperature sensor signal through a circuit. The circuit connects to a cavity of the PCM connector.

TESTING



See Figures 1, 2, 3, 4, 5 and 6



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Fig. Fig. 1: Wiring schematic for the IAT sensor-1993-95 models



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Fig. Fig. 2: Wiring schematic for the IAT sensor-1996-97 models



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Fig. Fig. 3: Intake air temperature sensor connector pin coding-1993-95 models



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Fig. Fig. 4: Using a jumper wire to test both of the pin connections in the sensor harness



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Fig. Fig. 5: Using a jumper wire to test the pin to ground



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Fig. Fig. 6: Intake air temperature sensor connector and PCM pin coding-1996-97 models

Before testing any electrical component, inspect the wiring and connectors for damage. Also wiggle the connectors to ensure a that they are firmly engaged.

  1. Disconnect the IAT sensor wiring.
  2.  
  3. Using the DRB III scan tool or equivalent, read the voltage of the sensor.
  4.  
  5. If the sensor voltage is above 4.0 volts, replace the sensor. If it is not above 4.0 volts perform the following:
    1. Turn the key to the OFF position.
    2.  
    3. Disconnect the PCM module.
    4.  

  6.  
  7. Using an ohmmeter, measure the resistance between the sensor signal and the sensor ground circuits. Refer to the accompanying wiring illustration.
  8.  
  9. If the resistance is below 5.0 ohms repair the short in the ground circuit.
  10.  
  11. Using an ohmmeter, probe the sensor signal circuit. If the resistance is below 5.0 ohms their is a short to ground in the signal circuit which must be repaired. If the resistance is above 5.0 ohms the PCM may be defective.
  12.  
  13. Using the DRB III scan tool or equivalent, read the sensor voltage.
  14.  
  15. If the temperature sensor voltage is not above 4.5 volts do the following.
    1. Using the illustration of the schematic, wiggle the sensor connection and harness. Monitor the DRB III or equivalent display.
    2.  
    3. Was there any sensor voltage change. If so repair the harness or connector short. If there was no change, the condition required is set to set the code is not present.
    4.  
    5. Using the schematic as a guide, inspect the wiring and connectors. Repair if needed. If all is OK, then the test is complete.
    6.  

  16.  
  17. If the sensor voltage is above 4.5 volts perform the following.
    1. Disconnect the IAT sensor and connect a jumper wire across the IAT signal and sensor ground circuits 1 and 2.
    2.  
    3. Read the voltage on the scan tool, is it below 1.0 volts. If it is, replace the IAT sensor.
    4.  
    5. If it is above 1.0 volts, move the jumper wire from the sensor ground to an engine ground. See the accompanying illustration.
    6.  
    7. If the voltage is below 1.0 volts, repair the open in the sensor ground circuit.
    8.  

  18.  
  19. If it is the voltage is above 1.0 volts, perform the following.
    1. Turn the key to the OFF position.
    2.  
    3. Disconnect the PCM.
    4.  
    5. Using an ohmmeter, test the IAT sensor signal from the PCM to the sensor connector.
    6.  
    7. If the resistance is below 5.0 ohms, the PCM may be faulty. If it is not, repair the open sensor signal circuit. REMOVAL & INSTALLATION
    8.  

  20.  

3.3L Engine
EXCEPT FLEX FUEL
  1. Disconnect the electrical wiring from the sensor.
  2.  
  3. Unscrew and remove the sensor from the rear of the intake manifold plenum.
  4.  

To install:
  1. Screw the sensor into the plenum and tighten to 100 inch lbs. (11 Nm).
  2.  
  3. Attach the electrical wiring to the sensor.
  4.  

FLEX FUEL

See Figure 7

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Fig. Fig. 7: Threaded into the plenum is the intake air temperature sensor-3.3 flex fuel engine

The intake air temperature sensor threads into the rear of the intake manifold plenum.

  1. Disconnect the electrical wiring from the sensor.
  2.  
  3. Unscrew and remove the sensor from the rear of the intake manifold plenum.
  4.  

To install:
  1. Screw the sensor into the plenum and tighten to 20 ft. lbs. (28 Nm).
  2.  
  3. Attach the electrical wiring to the sensor.
  4.  

3.5L Engine

See Figures 8, 9 and 10



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Fig. Fig. 8: The intake air temperature sensor threads into the center of the intake manifold plenum-3.5L engine



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Fig. Fig. 9: Remove the engine cover...



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Fig. Fig. 10: ... then you can access the intake air temperature sensor-3.5L shown

The intake air temperature sensor threads into the center of the intake manifold plenum.

  1. Remove the engine cover.
  2.  
  3. Disconnect the electrical wiring from the sensor.
  4.  
  5. Unscrew the sensor from the plenum.
  6.  

To install:
  1. Screw the sensor into the intake manifold plenum and tighten to 20 ft. lbs. (28 Nm).
  2.  
  3. Attach the electrical wiring to the sensor.
  4.  
  5. Install the engine cover.
  6.  

 
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