This sensor is a thermistor type, meaning as the temperature increases, the sensor resistance decreases. It is the same type of sensor as the CTS. The PCM sends a 5 volt reference signal to the sensor and interprets the voltage drop across the sensor to calculate engine intake air temperature.
See Figures 1
- If a code has been set and the vehicle has not been exposed to temperatures lower than -22°F (-30°), unplug the connector from the sensor and use the chart to check the sensor resistance with an ohmmeter.
- With the ignition switch ON , check for 5 volts to the sensor at connector terminal A , the tan wire.
If using a scan tool connected to the ALDL, the reading should be the same as the actual air temperature with the ignition switch
- If the reading is less than -22°F (-30°C), unplug the sensor connector and jumper the PCM terminals together. If the reading goes to above 266°F (130°C), the problem is in the sensor. If the reading does not change or go high enough, the problem is in the wiring or the PCM.
- If the reading is more than 284°F (140°C), unplug the sensor connector. If the reading goes below -22°F (-30°C), the problem is in the sensor. If it does not change or does not go low enough, the problem is in the wiring or the PCM.
- If a scan tool is available, allow the engine to cool to the ambient temperature overnight, then compare the CTS and ATS readings. Temperatures should be within 4 degrees of each other with the ignition ON and the engine not running.
REMOVAL & INSTALLATION
See Figures 2 and 3
- As an added safety precaution, you may wish to disable the air bag(s). refer to Chassis Electrical for the disabling procedures.
- Disconnect the negative battery cable.
- Remove the air inlet tube fasteners, then rotate the tube to access the sensor.
- Using your hand or a pair of pliers, gently squeeze the sides of the sensor electrical connector, then remove the connector from the sensor.
- Using a 13mm deep well socket, loosen and remove the sensor from the inlet duct.
- Install the sensor and tighten to 44 inch lbs. (5 Nm).
- Attach the sensor electrical connector.
- Install the air inlet tube using the fasteners.
- Connect the negative battery cable.
- If necessary, enable the air bag(s). refer to Chassis Electrical .