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How to Solve the Heating Issue in V.A.G. Group Cars

Model: Audi A4 B9 - Years: 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024
Part: Air conditioner

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Video tutorial

Before replacing parts on an Audi A4 B9 like the one in the video, it is advisable to diagnose with an OBD2 scanner to read any error codes related to the heating malfunction. The main causes are: the heating control valve, which shows symptoms of absent or intermittent heat.

The valve is located in the engine compartment, in the vacuum chamber under the windshield. To replace it, disconnect the electrical connector, unlock the coolant hoses, and remove and replace the valve.

If you feel little or no heat, often with the AC working, then the heater core is likely clogged: an accumulation of particles (silica gel from the expansion tank or scale) blocking the flow of hot coolant. The solution is to flush the heater (in extreme cases, replacement is required, but it involves removing the dashboard).

If it is impossible to adjust the airflow direction or temperature, then the issue is with the air blend doors. This is a very common failure identified by an OBD2 diagnosis.

If the heating is poor, especially at idle or with a cold engine, then look for the culprit in the auxiliary coolant pump, which ensures the flow of hot coolant even at low RPM.


Posted on 15 August 2026 by ScegliAuto


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by ScegliAuto

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