Circuit Description
The instrument panel integration module (IPM) monitors the left heater duct air temperature through the lower left air temperature sensor. The lower left air temperature sensor is a variable resistor. The IPM supplies 5 volts to the lower left air temperature sensor 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 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 lower 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 lower left air temperature sensor data by the IPM. The Driver Htr. Duct Temp displayed on the scan tool, -31°C (-23°F) in the HVAC Sensors data list, will be the default value. The Left Htr. Duct Temp displayed on the scan tool in the Open/Short Data list will be 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 lower left air temperature sensor data by the IPM. The Driver Htr. Duct Temp displayed on the scan tool, 119°C (246°F) in the HVAC Sensors data list, will be the default value. The Left Htr. Duct Temp displayed on the scan tool in the Open/Short Data list will be 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 by using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The operating range of the sensor is between 0.09-4.90 volts. If the scan tool displays a value between 0-.08 volt or 4.91-5.0 volts, then the sensor is performing outside of its designed limits.
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Tests for the proper operation of the circuit in the high voltage range.
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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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
Does the scan tool indicate that the Left Htr. Duct Temp parameter is within the specified range? | 0.09-4.90 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Does the scan tool indicate that the Left Htr. Duct Temp parameter is greater than the specified value? | 4.90 V | Go to Step 4 | Go to Step 5 | |
Does the scan tool indicate that the Left Htr. Duct Temp parameter is less than the specified value? | 0.09 V | Go to Step 8 | Go to Step 6 | |
5 | Test the lower left air temperature sensor signal circuit of the lower left air temperature sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 |
6 | Test the lower left air temperature sensor signal circuit of the lower left air temperature sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 7 |
7 | Test the low reference circuit of the lower left air temperature sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 |
8 | Inspect for poor connections at the harness connector of the lower left air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
9 | Inspect for poor connections at the harness connector of the instrument panel integration module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
10 | Replace the lower left air temperature sensor. Refer to Air Temperature Sensor Replacement - Lower Left Side . Did you complete the replacement? | -- | Go to Step 12 | -- |
11 |
Important: : Perform the recalibration procedure for the Instrument panel integration module. Replace the instrument panel integration module. Refer to Instrument Panel Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
