2020 Audi S4 Radiator Fan Isn't Working

Diagnosing the Causes of a Non-Functional Radiator Fan in Your 2020 Audi S4 and How to Fix It

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
34% chance it's the
Fan Motor or Clutch
0%
28% chance it's the
Fan Relay or Fuse
0%
23% chance it's the
Temp Sensor or Fan Control Module
0%
15% chance it's
Something else
The most common reasons a 2020 Audi S4 radiator fan isn't working are the fan assembly, the fan clutch, or the coolant temperature sensor.
  • Fan Motor or Clutch: A faulty fan motor or a malfunctioning fan clutch can result in inadequate cooling, causing the engine to overheat.
  • Fan Relay or Fuse: A faulty fan relay or blown fuse can prevent the cooling fan from operating, leading to engine overheating.
  • Temp Sensor or Fan Control Module: A faulty temperature sensor or fan control module can result in incorrect readings, causing the engine to overheat or the cooling fan to operate improperly.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2020 Audi S4 radiator fan isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Over time serpentine belts stretch, crack, and the ribs that ride on the accessory pulleys being to wear smooth. A squealing noise that increases with engine speed or as engine driven accessories are turned on may be noted. The noise is caused by the belt slipping on the pulleys, insufficiently driving them. Ineffective air conditioning, a battery warning light, or intermittent power steering assist can result from this.

»MORE: Symptoms of a bad serpentine belt

The bad thermostat can cause two different sets of problems, depending on whether it's stuck open or stuck closed.

A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. It may also cause poor fuel mileage and the heater to blow cool air.

A thermostat that is stuck closed will cause the vehicle to overheat. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to be checked for other issues.

» LEARN MORE: Signs of a bad thermostat, and how to fix it

When the engine coolant temperature sensor fails, it will send inaccurate information to the vehicle’s computer, causing the computer to react to false operating conditions. This will cause the engine to consume more fuel than normal, depleting fuel mileage, and causing black, sooty smoke from the engine under moderate to heavy acceleration. The check engine light will illuminate, and on-board diagnostic trouble codes may be stored for exhaust and emission system failure, fuel delivery system failure, and engine cooling system failure. Overheating may also occur, as the coolant sensor may be leaking fluid out of the engine, creating a an air pocket in the system.

What are the steps to diagnose the non-functioning radiator fan in a 2020 Audi S4?

To diagnose a non-functioning radiator fan in your 2020 Audi S4, begin with the simplest solutions before progressing to more intricate checks. Start by inspecting the fuse associated with the radiator fan; a blown fuse is a common culprit that can easily be replaced. If the fuse is intact, move on to the relay, as a malfunctioning relay can prevent the fan from receiving power. Next, test the fan motor directly by applying power to it; if it spins, the motor is likely functional. If the fan does not operate, check the temperature sensor, which is essential for activating the fan based on engine temperature. Additionally, inspect the wiring and connections for any signs of damage or loose connections that could disrupt power flow. Finally, utilize a diagnostic tool to scan for error codes that may provide insights into any underlying issues. By following this structured approach, you can effectively diagnose and address the radiator fan problem in your Audi S4, ensuring optimal vehicle performance.

What are the common causes for the radiator fan not working in a 2020 Audi S4?

When troubleshooting the radiator fan issue in a 2020 Audi S4, it's essential to consider several common problems that could be at play. A faulty fan motor is often the primary culprit, as it can fail to operate altogether, necessitating a replacement to restore functionality. Additionally, a blown fuse can interrupt the electrical flow to the fan, so checking the fuse box for any blown fuses is a straightforward first step. Another potential issue is a malfunctioning temperature sensor, which may fail to signal the fan to activate when the engine reaches a certain temperature; replacing this sensor can resolve the problem. Wiring issues, such as damaged or loose connections, can also prevent the fan from working properly, making it crucial to inspect the wiring for any visible problems. Lastly, low coolant levels can lead to overheating, which may cause the radiator fan to operate inefficiently or not at all; ensuring that the coolant is at the appropriate level can help maintain optimal engine temperature and fan performance. By systematically addressing these common causes, you can effectively diagnose and fix the radiator fan issue in your Audi S4.

How urgent is it to address the non-functioning radiator fan in a 2020 Audi S4?

Addressing a non-functioning radiator fan in a 2020 Audi S4 is of utmost urgency due to the significant risks it poses to your vehicle's engine health. The radiator fan plays a vital role in maintaining optimal engine temperatures by dissipating heat from the radiator. If the fan fails, the engine can quickly overheat, leading to severe consequences such as warped components or even engine seizure. These issues not only result in costly repairs but can also necessitate a complete engine replacement, which is a financial burden that many car owners wish to avoid. By promptly diagnosing and fixing the radiator fan issue, you can prevent further damage and ensure that your Audi S4 operates efficiently and safely. Therefore, if you notice any signs of fan malfunction, it is crucial to take action immediately to safeguard your vehicle's performance and longevity.

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2020 Audi S4 Radiator Fan Issues: Causes & Repairs