[claykin]

Washer fluids with claims such as de-icing, bug and tar, etc should be avoided. These fluids contain additives designed to add a coating to the windshield. This coating can get on the electric sensor in the washer reservoir and block the electric pulse that flows between the sensor pins.

Some affected claim sensor replacement was needed, others say they resolved the issue by flushing out the reservoir (likely several times) to clear the chemical product. Seems BMW, Mercedes and VW products are on top of the list of affected cars.