• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Inside Air Temperature Sensor Blower Ignition | 1 | 1 | -- | -- |
Ambient Air Temperature Sensor Signal | B0159 | B0159 | B0159 | -- |
Inside Air Temperature Sensor Signal | B0164 | B0164 | B0164 | -- |
Upper Left Air Temperature Sensor Signal | B0174 | B0174 | B0174 | -- |
Upper Right Air Temperature Sensor Signal | B0510 | B0510 | B0510 | -- |
Lower Left Air Temperature Sensor Signal | B0179 | B0179 | B0179 | -- |
Lower Right Air Temperature Sensor Signal | B0515 | B0515 | B0515 | -- |
Inside Air Temperature Sensor Blower Control | 1 | 1 | 1 | -- |
Ambient Air Temperature Low Reference | -- | B0159 | -- | -- |
Inside Air Temperature Low Reference | -- | B0164 | -- | -- |
Upper Left Air Temperature Low Reference | -- | B0174 | -- | -- |
Upper Right Air Temperature Low Reference | -- | B0510 | -- | -- |
Lower Left Air Temperature Low Reference | -- | B0179 | -- | -- |
Lower Right Air Temperature Low Reference | -- | B0515 | -- | -- |
1. Inside air temperature sensor malfunction |
The HVAC control module monitors air temperature through air temperature sensors. 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 HVAC control module requests A/C compressor clutch engagement and controls the appropriate mode and air temperature actuator door positions in order to maintain the selected air temperature on the HVAC control module.
The inside air temperature sensor provides the HVAC control module with the temperature of the air drawn through an aspirator from the passenger compartment across a sensor. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases and the voltage signal decreases. As the air temperature decreases, the resistance increases and the voltage signal increases.
The ignition is ON.
The HVAC control module detects the air temperature sensor signal circuit is less than 2 counts or greater than 253 counts for 30 seconds.
A default value will be used for the sensor data by the HVAC control module.
• | The DTC will become history if the HVAC control module no longer detects a failure. |
• | The history DTC will clear after 50 fault-free ignition cycles. |
Control Module References for scan tool information
⇒ | 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. |
⇒ | If less than the specified range, test the signal circuit terminal A for a short to ground. 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 or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
⇒ | 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. |
⇒ | If less than the specified range, test the signal circuit terminal 1 for a short to ground. 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 or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for HVAC control module replacement, setup, and programming |