B0510
DTC B0174, B0179, B0510, or B0515
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B0174
- Range/Performance Output Air Temperature Sensor 2 Circuit
DTC B0179
- Range/Performance Output Air Temperature Sensor 3 Circuit
DTC B0510
- Range/Performance Output Air Temperature Sensor 4 Circuit
DTC B0515
- Range/Performance
Diagnostic Fault Information
Circuit/System Description
The HVAC control module supplies the air duct temperature sensors with a low reference circuit and 5-volt signal circuit. The HVAC control module determines the voltage drop across the sensor, which is proportional to temperature. As the air temperature increases, the sensor resistance decreases and the voltage signal decreases. As the air temperature decreases, the sensor resistance increases and the voltage signal increases.
* Output Air Temperature Sensor 1 refers to the upper left air duct temperature sensor
* Output Air Temperature Sensor 2 refers to the lower left air duct temperature sensor
* Output Air Temperature Sensor 3 refers to the upper right air duct temperature sensor
* Output Air Temperature Sensor 4 refers to the lower right air duct temperature sensor
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
The HVAC control module detects the inside air temperature sensor signal circuit is less than -36°C (-38°F) or greater than 215°C (419°F) for greater than 15 seconds.
Action Taken When the DTC Sets
The system operates using a default value.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 50 fault-free ignition cycles.
Circuit/System Verification
Ignition ON, observe the appropriate scan tool air duct temperature sensor. The reading should be between -35°C (-39°F) and 98°C (208°F) and change with duct air temperature changes.
Circuit/System Testing
Important: If an air duct temperature sensor has an out of range condition caused by a short to voltage, short to ground, or an open/high resistance, the scan tool will display the same value: 39°F (4°C).
1. Ignition OFF, disconnect the harness connector at the appropriate air duct temperature sensor.
2. Ignition OFF, test for less than 10 ohms of resistance between the low reference circuit terminal 2 and ground.
^ If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
3. Ignition ON, test for 4.8-5.2 volts between the low reference circuit terminal 2 and the signal circuit terminal 1.
^ If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the HVAC control module.
^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
4. If all circuits test normal, test or replace the air duct temperature sensor.
Component Testing
1. Test the air duct temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the Temperature VS Resistance table Sensor Resistance Table and verify that the resistance is within 5 percent of the specification.
^ If not within the specified range, replace the sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Air Temperature Sensor Replacement - Upper Right Side
* Air Temperature Sensor Replacement - Upper Left Side
* Air Temperature Sensor Replacement - Lower Left Side
* Air Temperature Sensor Replacement - Lower Right Side