Air temperature sensor (T4000)
1.Check if the temperature sensor shows a static value ( e.g. check the temperature signal in SDP3. Hold the temperature sensor in the hand ) 2. Check that the temperature sensor is correctly mounted 3. Check the wiring to the sensor and the connector 4. If no other fault has been found, replace the temperature sensor and erase the fault codes
What you'll see
No driver-visible symptom recorded.
System reaction
This fault affects the engine emissions of nitrogen oxides. Depending on which emission regulations are fulfilled, torque reduction, speed limitation and warning lamp can be activated.
Diagnostic depth
Temperature sensor stuck. Sensor value does not change over a long time period. T202, T126 or T4000.
Wiring / connector Faulty sensor Manipulated temperature sensor T202, T126 or T4000