Audi Q5 Engine Coolant Temperature Sensor Guide (2014-2018)
Is a faulty temperature sensor causing engine problems in your Audi Q5? Here’s what you need to know before you buy a replacement.
- A bad ECT sensor can cause poor fuel economy, overheating, and a Check Engine Light (P0118).
- Before buying, check your original sensor's color and pin-count to ensure you order the correct part.
- For Audi electronics, it's wise to invest in reputable aftermarket brands like Hella, Delphi, or Vemo to ensure reliability.
- Be aware of the separate safety recall for the electric coolant *pump* on 2.0T models, which is a different component.
Is Your Audi Q5 Acting Up? It Could Be the Coolant Temp Sensor
If your 2014-2018 Audi Q5 is experiencing issues like poor fuel economy, a lit Check Engine Light, or an engine that's running too hot or too cold, a faulty Engine Coolant Temperature (ECT) sensor could be the culprit. This sensor plays a key role in how your engine performs, and when it fails, it can cause a range of noticeable problems. This guide will help you understand the symptoms, choose the right aftermarket replacement part, and know what to expect during the repair.
Symptoms of a Failing ECT Sensor
A bad coolant temperature sensor can make your Q5's computer think the engine is colder or hotter than it actually is. This leads to incorrect adjustments and can cause several issues:
- Check Engine Light: The most common sign is a Check Engine Light with codes like P0118, which points to a circuit problem with the sensor.
- Poor Fuel Economy: If the sensor incorrectly tells the computer the engine is cold, the system will inject extra fuel, hurting your gas mileage.
- Engine Overheating: A faulty sensor may fail to trigger the cooling fans when needed, causing the engine to overheat. Conversely, the fans might run all the time, even when the engine is cold.
- Rough Idling or Misfires: Incorrect fuel and timing adjustments can lead to a shaky, unstable idle.
- Black Smoke from Exhaust: This is a sign of a rich fuel mixture, where too much fuel is being burned because the computer thinks the engine is cold.
- Hard Starting: The engine may be difficult to start, especially when cold, if the fuel mixture is incorrect.
Important: Coolant PUMP Recall vs. Coolant TEMP Sensor
Many 2013-2017 Audi Q5s with the 2.0L TFSI engine were part of a major safety recall for a faulty electric coolant pump, which could overheat and cause a fire. This is a separate part from the Engine Coolant Temperature Sensor. While both are part of the cooling system, a bad sensor will not be fixed by the pump recall. Verify any open recalls for your vehicle with the NHTSA or an Audi dealer.
Choosing the Right Aftermarket Sensor
When it comes to electronic parts on a German vehicle like your Audi, quality matters. While a cheap sensor might seem tempting, it can fail prematurely or provide inaccurate readings, leading to the same problems you were trying to fix. It's often best to choose a brand known for supplying original equipment (OEM) parts or one with a strong reputation.
Here’s a breakdown of available brands into tiers:
- OEM-Quality Aftermarket (Recommended): Brands like Hella, Delphi, NGK, and Vemo have a strong reputation for producing reliable sensors for European vehicles. These are often the safest bet for a long-lasting, trouble-free repair.
- Standard Aftermarket: Brands such as Beck Arnley, Standard Ignition (SMP), and Four Seasons offer a balance of value and quality. They are generally reliable for most repairs.
- Value-Oriented Brands: Other brands may offer the lowest price, but quality can be inconsistent for sensitive electronic components on an Audi. For a critical sensor like the ECT, investing a few extra dollars in a higher-quality part is a wise choice to avoid future headaches.
Pro Tip: Check Your Original Part First!
Audi used different sensors (e.g., green 4-pin vs. grey 2-pin) across different engine types and years. Before ordering, it is highly recommended to visually inspect your Q5's current sensor to confirm its color and the number of pins on the electrical connector. This will ensure you purchase the correct part and avoid installation delays.
Cost of Replacing the Audi Q5 ECT Sensor
The cost to replace the sensor is reasonable, especially if you can do it yourself. The part itself is not expensive, and the labor is straightforward for a mechanic.
| Item | Estimated Cost |
|---|---|
| New Aftermarket ECT Sensor | $13 - $62 |
| New OEM ECT Sensor | $30 - $50 |
| Shop Labor | $75 - $150 |
| Total Estimated Cost (Shop Repair) | $105 - $212 |
Frequently Asked Questions (FAQ)
Is this a difficult repair to do myself?
For a DIYer with some experience, this is a manageable job. The main challenges are locating the sensor (which can be difficult to see) and accessing it, as the space can be tight. You will need basic tools, and you should be prepared for a small amount of coolant to spill. Always work on a cool engine.
Where is the ECT sensor located on my 2014-2018 Audi Q5?
The location can vary depending on your engine (2.0T, 3.0T, etc.). It is generally found screwed into a coolant passage, often on a coolant flange on the cylinder head, near the thermostat housing, or on a coolant pipe near the radiator. Searching for a video or diagram specific to your Q5's engine is the best approach.
Do I need to drain all the coolant to replace the sensor?
No, you do not need to drain the entire system. Only a small amount of coolant will leak out when you remove the old sensor. Have the new sensor ready to install quickly to minimize the loss. Make sure to top off the coolant reservoir with the correct type of Audi-approved coolant (G12/G13) afterward.
Can I just ignore the problem if the car still drives?
It is not recommended. Driving with a bad ECT sensor can lead to long-term engine damage from overheating, poor performance, and significantly reduced fuel efficiency. It can also cause your vehicle to fail an emissions test. For the low cost of the part, it's a repair that should be done promptly.
Helpful Videos
Technical Specifications
OEM Part Numbers: 06A919501A 059919501A 078919501C
Typically a 2-pin or 4-pin thermistor sensor. Color (e.g., green, grey, black) is a key identifier for different versions.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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- Is Your Audi Q5 Acting Up? It Could Be the Coolant Temp Sensor
- Symptoms of a Failing ECT Sensor
- Important: Coolant PUMP Recall vs. Coolant TEMP Sensor
- Choosing the Right Aftermarket Sensor
- Pro Tip: Check Your Original Part First!
- Cost of Replacing the Audi Q5 ECT Sensor
- Frequently Asked Questions (FAQ)
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