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Check Engine Light (P0299) and Loss of Power on 2017 Q3 Prestige

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Mike T. · rep 0 · May 26, 3:46 AM · 1 replies · solved · Question

Vehicle: 2017 Audi Q3 Prestige

Hello everyone,

My 2017 Audi Q3 Prestige (2.0 TFSI Quattro) recently threw a Check Engine Light, and when I scanned it, I got a P0299 code. Along with the light, I've noticed a significant loss of power, especially during acceleration. The car feels sluggish, almost like the turbo isn't kicking in properly.

I also sometimes hear a slight whistling or whooshing sound from the engine bay when I accelerate, which wasn't there before. The car has about 70,000 miles on it. I'm worried it might be something serious with the turbocharger.

Has anyone dealt with a P0299 code on their Q3? What was the culprit for you? Trying to get an idea of what I might be looking at.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 26, 3:46 AM

0

ClearTheCode admin answer:

The P0299 code indicates an 'Engine Underboost' condition, meaning your engine's turbocharger is not producing the expected level of boost pressure. This is a common issue on turbocharged Audi engines, including your 2017 Q3's 2.0 TFSI. The loss of power and whistling sound are classic symptoms. Here are the most common causes:

  1. Boost Leaks: This is often the most frequent cause. Check all intercooler hoses, charge pipes, and vacuum lines for cracks, loose clamps, or disconnections. A small leak can significantly reduce boost pressure and create a whistling sound.

  2. Diverter Valve (DV) Failure: The diverter valve is responsible for releasing excess boost pressure when you lift off the throttle. If it's stuck open or leaking, boost pressure will escape, leading to underboost. Older plastic piston-style DVs are more prone to failure; newer revisions are typically diaphragm-style.

  3. Wastegate Actuator/Flapper Issues: The wastegate controls exhaust flow to the turbo turbine. If the wastegate actuator (which controls the wastegate) is faulty or the wastegate flapper itself is sticking open, boost pressure will be insufficient. This can sometimes be diagnosed by checking the actuator rod for free movement.

  4. PCV Valve Failure: A failing PCV (Positive Crankcase Ventilation) valve can create a vacuum leak, which can sometimes manifest as an underboost condition or other engine performance issues. While less direct, it's worth checking.

  5. Turbocharger Failure (Less Common): While possible, actual turbocharger failure (e.g., worn bearings, damaged turbine) is less common than the above issues but can certainly cause P0299. You might notice excessive oil consumption or smoke from the exhaust in such cases.

When to See a Shop:

Given the P0299 code and noticeable performance issues, it's recommended to have your Q3 inspected by an Audi specialist or dealership. They have the necessary diagnostic tools to perform a smoke test to find boost leaks, check turbocharger performance, and accurately pinpoint the root cause of the underboost condition. Addressing this promptly will prevent potential long-term engine damage.

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