Audi A3 - Engine starts badly | HELLA

If a customer complains about the above error, this could be caused by the coolant temperature sensor and / or its connection cable to the engine control unit. The customer may also complain of poor engine running. Error codes 16500, 16501 and 16502 may be output when reading out the event memory. These indicate a functional fault in the coolant temperature sensor. In this case, proceed as follows:

- Disconnect the plug connection at the engine control unit and the coolant temperature sensor.

- Check the cable for continuity. The ohmic resistance must be less than 1 Ohm.

- Check the contact pins in the plug connections for corrosion and clean if necessary.

- Check the ground connections.

If no fault is identified, check that the temperature sensor itself is functioning. This can be done by measuring the resistance between PIN 1 and 3. Three following reference values apply:

20°C = 2250 - 2950 Ohm

60°C = 530 - 675 Ohm