Intake Air Sensor — Removal, Checking and Installation (Mercedes-Benz C-Class W202)

The temperature sensor measures the temperature of the intake air. This value, together with the signal from the intake manifold pressure sensor (pMS management system) serves as a criterion for assessing the amount of air being admitted. The intake air temperature sensor is an NTC resistor (NTC – negative temperature coefficient), the resistance of which decreases with increasing temperature.

The temperature sensor is located on the left side of the air filter cross pipe.

Removal

Remove the temperature sensor together with the plug connector by squeezing both clamps (arrows).

Examination

1. Remove the plug connector.

2. Suspend the thermometer in a water bath and heat it slowly.

3. Check the resistance of the temperature sensor with an ohmmeter. The measured value is considered normal if it is within the 5% tolerance (see table Temperature sensor resistance).

4. If the temperature sensor does not reach the specified values during measurements, it should be replaced.

Installation

1. Place the plug connector on the wire.

2. Check the O-ring for damage and porosity.



3. Insert the temperature sensor with the sealing ring. Press the brackets outward until they click into place.

Temperature sensor resistance

Temperature	Resistance
+10°C	approx. 9670 Ohm
+20°C	approx. 6060 Ohm
+30°C	approx. 3900 Ohm
+40°C	approx. 2600 Ohm
+50°C	approx. 1760 Ohm
+60°C	approx. 1220 Ohm
+70°C	approx. 860 Ohm
+80°C	approx. 620 Ohm