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Home >> Chrysler >> 2002 >> Intrepid Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Modules >> System Tests >> Heating & A/C Systems >> In Car Temp Sensor Failure (ATC Aspirator Failure)
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In Car Temp Sensor Failure (ATC Aspirator Failure)

NOTE: After making any repairs, perform BODY VERIFICATION TEST  under VERIFICATION TESTS.

Monitored & Set Condition

  1. When Monitored: With the ignition on.
  2. Set Condition: The BCM detects an abnormally high voltage (above 4.8 volts) or an abnormally low voltage (below .31 volt) on the in-car temperature sensor signal.

Possible Causes:

Testing

  1. Turn ignition on. Completely cover the aspirator inlet, below blower switch, with a piece of tissue paper. Turn ignition off. Stay in vehicle, close all doors and ensure courtesy lights are off. Wait 3 minutes. Open and close driver door and observe the aspirator motor. The motor should run for approximately 30 seconds after the courtesy lights have faded out and then stop. Disconnect the ATC head harness connector. See Figure . Turn ignition on. Measure the voltage of the in-car temperature sensor signal circuit. The voltage should be between 4.5-5.2 volts. If the aspirator never ran, go to next step. If the aspirator timer was inoperative when door opened, go to step  6 . If the in-car temperature sensor is 5.3 volts or more, repair the in-car temperature sensor signal circuit for a short to voltage. If the circuit is OK, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If the in-car temperature sensor is 4.5 volts or less, go to step  7 . If none of these findings were found, go to step  10 .
  2. Measure the voltage of the fused B+ circuit. If the voltage is 10 volts or more, go to next step. If the voltage is 10 volts or less, repair the fused B+ circuit for an open.
  3. Measure the voltage of the aspirator motor driver circuit. If the voltage is 10 volts or more, repair the aspirator motor driver circuit for a short to voltage. If circuit is OK, replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If the voltage is 10 volts or less, go to next step.
  4. Disconnect the BCM C2 harness connector. See Figure . Measure the resistance of the aspirator motor driver circuit between the BCM C2 connector and the ATC head connector. If the resistance is 5 ohms or less, go to next step. If the resistance is 5 ohms or more, repair the aspirator motor driver circuit for an open.
  5. Reconnect the ATC head harness connector. Connect a jumper wire between the aspirator motor driver circuit and ground. Check the operation of the aspirator motor fan. If the aspirator motor is running, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If the aspirator motor is not running, replace the automatic temperature control head. See AUTOMATIC A/C-HEATER SYSTEMS - CONCORDE, INTREPID & 300M article in HVAC.
    6. NOTE: Ensure the courtesy lights operate properly from the drivers door before proceeding. If not, see INTERIOR LIGHTING SYSTEMS 
    NOTE: This path is for the aspirator continuing to run with the key OFF and the doors closed.
  6. If the aspirator motor stops running, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If the aspirator motor does not stop running, repair the aspirator motor driver circuit for a short to ground.
  7. Turn ignition off. Disconnect ATC head harness connector. Measure the resistance between ground and the in-car temperature sensor signal circuit. If the resistance is 5 ohms or less, repair the in-car temperature sensor signal circuit for a short to ground. If the resistance is 5 ohms or more, go to next step.
  8. Disconnect the BCM C1 harness connector. See Figure . Measure the resistance between the sensor ground circuit and the in-car temperature sensor signal circuit in the ATC head connector. If the resistance is 5 ohms or less, repair the in-car temperature sensor signal circuit for a short to the sensor ground circuit. If the resistance is 5 ohms or more, go to next step.
  9. Backprobe one voltmeter lead to the in-car temperature sensor signal circuit in the BCM C2 connector and the other lead to ground. Reconnect the BCM C1 & C2 harness connectors. Turn the ignition on and observe the voltmeter. If the voltage is 4.5 volts or more, repair the in-car temperature sensor signal circuit for an open. If the voltage is 4.5 volts or less, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION.
  10. Close the driver door latch and ensure all lights are off. Wait one minute to allow the BCM to go to sleep. Measure the resistance between ground and the sensor ground circuit. If the resistance is 10 ohms or less, go to next step. If the resistance is 10 ohms or more, go to step  12 .
  11. Reconnect the ATC head harness connector. With the scan tool, erase BODY COMPUTER DTC'S. Turn ignition on. With the scan tool, read BODY COMPUTER DTC's. If the scan tool displays IN-CAR TEMP SENSOR failure DTC, replace the automatic temperature control head. See AUTOMATIC A/C-HEATER SYSTEMS - CONCORDE, INTREPID & 300M article in HVAC. If no, the aspirator and in-car temperature sensor should be fully operational.
  12. Backprobe one ohmmeter lead to the sensor ground circuit in the BCM C1 connector and the other lead to ground. Reconnect the BCM C1 harness connector. Close the driver door latch and ensure all lights are off. Wait one minute to allow the BCM to go to sleep. Measure the resistance between ground and the sensor ground circuit. If the resistance is 10 ohms or less, repair the sensor ground circuit for an open. If the resistance is 10 ohms or more, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION.
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