Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Outside Temperature Sensor
The function of the outside temperature sensor is to detect the vehicle's ambient temperature. The ambient temperature is required so that the engine control module (ECM) can regulate, among other things:
- the engine cooling fan (FC)
- the air conditioning (A/C) compressor's displacement.
The ambient temperature is also used as a substitute value in the event of a fault in certain components or functions and to control certain diagnostic functions.
The engine control module (ECM) supplies other control modules with the current outside temperature by transmitting information on the controller area network (CAN).
The temperature sensor is a resistor with a negative temperature coefficient, so called NTC type. It is supplied with power from the control module.
The resistance in the sensor changes according to the ambient temperature of the vehicle. This provides the engine control module (ECM) with a signal of between 0-5 V. Low temperature results in high resistance (high voltage). High temperature results in low resistance (low voltage).
The outside temperature sensor is positioned in the left door mirror.
The engine control module (ECM) can diagnose the outside temperature sensor. The sensor value can be read off using the diagnostic tool.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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