Audi Coolant Light Is Quirky

This bulletin applies to Audis from 2017-2021.

If a customer complains of the coolant light remaining on, but the coolant level is within specifications, check the following. Due to the large coolant circuit capacity, there is significant fluctuation in the coolant level when the coolant cools down and heats up. If the coolant circuit is incorrectly filled or bled, this can lead to sporadic illumination of the low coolant level warning light. 

To diagnose the concern, follow these steps:

1. The coolant level in the expansion tank must be set/checked according to the Elsa repair manual while the engine is cold.  
2. The connector (including pins and contacts) should be checked carefully.
3. The contact surface of the pins and connector must be free of dirt and must not be damaged.
4. After unplugging and plugging the connector back in, perform a key cycle and check if the concern returns again. If it does, then continue with normal diagnosis outside of this TSB.