B0174

CIRCUIT DESCRIPTION
The instrument panel integration module (IPM) monitors the left A/C duct air temperature through the upper left air temperature sensor. The upper left air temperature sensor is a variable resistor. The IPM supplies 5 volts to the upper left air temperature sensor signal circuit and provides a low reference circuit. When the air is cold, the sensor resistance and signal voltage are high. When the air is warm, the sensor resistance and signal voltage are low. The IPM requests A/C compressor clutch engagement and controls the left air temperature door position in order to maintain the selected air temperature on the HVAC control module.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
The IPM detects the upper left air temperature sensor signal circuit is less than 0.09 volt (5 counts) or greater than 4.90 volts (250 counts).

ACTION TAKEN WHEN THE DTC SETS
^ When the ambient air temperature is at or below 15°C (59°F), a default value of 4.80 volts (245 counts) will be substituted for the upper left air temperature sensor data by the IPM. The Left AC Duct Temp. displayed on the scan tool is the default value. The Left AC Duct Temp displayed on the scan tool in the Open/Short Data list is the actual value.
^ When the ambient air temperature is at or above 16°C (60°F), a default value of 0.19 volt (10 counts) will be substituted for the upper left air temperature sensor data by the IPM. The Left AC Duct Temp. displayed on the scan tool is the default value. The Left AC Duct Temp displayed on the scan tool in the Open/Short data list is the actual value.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the IPM no longer detects a failure.
^ The history DTC will clear after 50 fault free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-3:

Steps 4-12:

The numbers below refer to the step numbers on the diagnostic table.
2. The operating range of the sensor is between 0.09-4.90 volts. If the Scan tool displays a value between 0-0.08 volts or 4.91-5.0 volts, then the sensor is performing outside of its designed limits.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.