DTC P0072: Ambient Temp Sensor Low: Testing
- Turn ignition on, engine not running. With the DRBIII®, read the ambient air temperature sensor voltage. If the voltage is below .4 volt, go to next step. If the voltage is not below .4 volt, see INTERMITTENT CONDITIONS . See POWERTRAIN VERIFICATION TEST VER-5 .
- Turn the ignition off. Disconnect the Ambient Air Temperature sensor harness connector. Turn ignition on, engine not running. With the DRBIII®, read Ambient Air Temprature sensor voltage. If the voltage is between 4.8 and 5.2 volts, replace the Ambient Air temperature sensor. See POWERTRAIN VERIFICATION TEST VER-5 . If the voltage is not between 4.8 and 5.2 volts, go to next step.
- Turn the ignition off. Disconnect the Ambient Air Temperature Sensor harness connector. Disconnect the PCM harness connector. Measure the resistance between ground and the (K145) AAT Signal circuit in the Ambient Air Temperature Sensor harness connector. If the resistance is below 100 ohms, repair the short to ground in the (K145) AAT signal circuit. See POWERTRAIN VERIFICATION TEST VER-5 . If the resistance is not below 100 ohms, go to next step.
- Turn the ignition off. Disconnect the Ambient Air Temperature sensor harness connector. Disconnect the PCM harness connector. Measure the resistance between the (K145) AAT Signal circuit and the (K167) sensor ground circuit in the Ambient Air temperature sensor harness connector. If the resistance is below 100 ohms, repair the (K167) sensor ground shorted to the (K145) AAT signal circuit. See POWERTRAIN VERIFICATION TEST VER-5 . If the resistance is not below 100 ohms, go to next step.
- If there are no possible causes remaining, replace and program the PCM. See PROGRAMMING . Perform POWERTRAIN VERIFICATION TEST VER-5 .
NOTE:
After the repair of the Ambient Air Temperature sensor DTC. The AAT sensor value will not be refreshed on the DRBIII® unless the vehicle has been driven at a speed greater then 20 MPH for more than 2 minutes.
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.