Circuit Description
The duct air temperature sensor is a thermistor used to control the signal voltage in the electronic climate control module. The electronic climate control module supplies a reference voltage (about 5 volts) on CKT 404 (BRN) to the sensor. When the upper duct air temperature is cold, the thermistor resistance is high. Therefore, the electronic climate control module will receive a high voltage input. If the upper duct air temperature is hot, the thermistor resistance is low. Therefore, the electronic climate control module will receive a low signal voltage input. The duct air temperature sensor is used to enhance the temperature control. Refer to Sensor Resistance Table .
Conditions for Setting the DTC
When the ignition switch is in the ON position, the electronic climate control module will detect DTC B0175 any time CKT 404 (BRN) is at or near zero voltage.
Action Taken When the DTC Sets
The electronic climate control module will use a default value of 10 A/D counts until the fault is cleared.
Conditions for Clearing the MIL/DTC
This fault will clear as soon as the fault goes away or has been repaired. The system will then return to normal operation. History DTCs can only be cleared by removing and restoring B+ or by using the scan tool.
Diagnostic Aids
| • | The electronic climate control module may set class 2 lost communication DTCs when the body control module (BCM) or the vehicle control module (VCM) is being reprogrammed. After reprogramming, inspect for DTCs in the electronic climate control module. Clear any history U DTCs, then resume diagnostics. |
| • | Visually inspect the sensor connector and harness for corrosion and damage. The resistance value of the sensor must be witin 334-100,0865 ohms. Refer to Sensor Resistance Table . If resistance is not within specifications, replace the sensor. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step measures the resistance of the duct air temperature sensor.
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This step inspects for a short to ground in CKT 404.
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This step inspects for intermittents and tests for a malfunctioning electronic climate control module.
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This step repairs the short to ground in CKT 404.
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This step replaces defective duct air temperature sensor.
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This step replaces a defective electronic climate control module.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Tools Required
| ||||||||
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check | ||||
Is the resistance within the range specified in the table? | -- | Go to Step 3 | Go to Step 6 | |||||
Is continuity present? | -- | Go to Step 5 | Go to Step 4 | |||||
Does the DTC reset? | -- | Go to Step 7 | Go to Intermittents and Poor Connections Diagnosis in Wiring Systems | |||||
Repair the short to ground in CKT 404 (BRN). Is the repair complete? | -- | Go to Diagnostic System Check | -- | |||||
Replace the duct air temperature sensor. Is the replacement complete? | -- | Go to Diagnostic System Check | -- | |||||
Replace the electronic climate control module. Is the replacement complete? | -- | Go to Diagnostic System Check | -- | |||||
