B0509 - Output Air Temperature Sensor 3 Circuit
Possible causes
- Faulty Output Air Temperature Sensor 3
- Output Air Temperature Sensor 3 harness is open or shorted
- Output Air Temperature Sensor 3 circuit poor electrical connection
- Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
Tech notes
B0509 05: Output Air Temperature Sensor 3 Circuit Short to Battery or OpenB0509 02: Output Air Temperature Sensor 3 Circuit Short to Ground
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B0509 Description
Air temperature sensors allow the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the discharge air in the HVAC ducts. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. When the duct air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the duct air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where 1 volt is approximately equal to 51 counts.
B0509 Information for specific makes
- B0509 BUICK Output Air Temperature Sensor 3 Circuit
- B0509 CADILLAC Output Air Temperature Sensor 3 Circuit
- B0509 CHEVROLET Output Air Temperature Sensor 3 Circuit
- B0509 GMC Output Air Temperature Sensor 3 Circuit
Related Information
B0509 Comments
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