What is the normal resistance of a car's outdoor temperature sensor?
2 Answers
The resistance of an outdoor temperature sensor is typically around 5kΩ. In most vehicles, when there is a malfunction with the outdoor temperature sensor, the dashboard will display abnormal temperature readings. This can lead to a distorted air-fuel ratio in the engine and may cause the air conditioning system to operate improperly or not at all. Related information is as follows: 1. Function: The car's outdoor temperature sensor detects the ambient temperature and transmits the detected temperature to the engine's ECU, converting it into an electrical signal. This determines the temperature setting of the automatic air conditioning system without manual intervention, adjusting the air conditioning to the most suitable temperature. 2. Normal temperature resistance: The outdoor temperature sensor, also known as the ambient temperature sensor, is usually installed near the front bumper or grille. Its sensing element uses a negative temperature coefficient thermistor. The detection method for the outdoor temperature sensor is the same as that for the coolant temperature sensor. Its resistance can be measured using the resistance setting of a multimeter. The normal resistance at room temperature should be between 1.6 to 1.8kΩ, with the resistance increasing as the temperature decreases. If the resistance value exceeds the specified range, it indicates an open circuit in the sensor wiring harness or poor contact at the connector, which can affect the normal operation of the vehicle's air conditioning system. Further inspection or replacement is recommended in such cases.
I previously encountered an issue with inaccurate outdoor temperature display, and after some troubleshooting, I found that the sensor's resistance was faulty. Normally, the resistance value varies between 2000 and 10000 ohms. For most car models, at room temperature (20 to 25 degrees Celsius), it's typically around 5,000 or 10,000 ohms. When the temperature rises, the resistance decreases, and conversely, it increases in colder conditions. A faulty sensor can cause the air conditioning to adjust airflow incorrectly or display wrong temperatures, making you unbearably hot in summer or freezing in winter. To check if it's working properly, it's best to unplug the sensor connector and measure the resistance with a multimeter. If the value deviates significantly from the common range (e.g., less than 1,000 ohms or more than 15,000 ohms), it might be time for a replacement. Be careful not to touch the circuit board when testing it yourself—safety first. Also, regularly check that the sensor isn't covered by mud or leaves to extend its lifespan.
