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2017 Q50 3.0t experiencing power loss and P0299 code – Turbo issue?

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Mark S. · rep 0 · May 22, 5:11 AM · 1 replies · solved · Question

Vehicle: 2017 Infiniti Q50 3.0t Red Sport

Hey everyone, I'm looking for some advice on my 2017 Infiniti Q50 3.0t Red Sport. Recently, I've noticed a significant drop in power, especially when accelerating hard. It feels like the car just isn't getting the boost it used to.

The check engine light came on, and when I scanned it, I got a P0299 code, which I understand means 'Turbocharger/Supercharger Underboost'. I'm really hoping it's not a major turbo failure, as I've heard those can be incredibly expensive on these cars.

Has anyone else experienced this with their Q50 3.0t? What were the common culprits you found? I'm trying to get an idea of what I might be looking at in terms of repair costs and complexity before I take it to the dealership. Any insights or diagnostic tips would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:11 AM

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ClearTheCode admin answer: The P0299 code on your 2017 Infiniti Q50 3.0t Red Sport indicates an underboost condition, meaning the engine's boost pressure is lower than expected. This is a common issue with the VR30DDTT engine and can stem from several sources. Addressing it promptly is crucial to prevent further damage.

Here are the common causes and diagnostic steps:

  1. Boost Leaks: This is often the simplest and most frequent cause. Check all intercooler piping, charge pipes, and vacuum lines for cracks, loose connections, or damaged O-rings. A smoke test performed by a shop can quickly identify these leaks.
  2. Wastegate Actuator Issues: The wastegate actuators on the VR30DDTT turbos can fail or become sticky. If an actuator isn't closing properly, exhaust gases bypass the turbine, leading to insufficient boost. This often requires specialized diagnostic tools to check actuator movement and position.
  3. Turbocharger Failure: While less common than leaks or actuators, a failing turbocharger (e.g., worn bearings, damaged turbine wheel) can cause underboost. You might hear unusual whining or grinding noises, or see excessive smoke from the exhaust.
  4. Boost Pressure Sensor (MAP Sensor) Malfunction: A faulty MAP sensor can send incorrect readings to the ECU, causing it to command less boost than necessary or misinterpret actual boost levels. This is relatively inexpensive to replace if confirmed faulty.
  5. Catalytic Converter Restriction: A severely clogged catalytic converter can create excessive back pressure, hindering turbo performance and leading to underboost. This is usually accompanied by other performance issues and sometimes a rotten egg smell.

When to See a Shop: Given the complexity of the VR30DDTT engine and its turbo system, it's highly recommended to have a qualified Infiniti specialist or a reputable independent shop diagnose this issue. They have the necessary diagnostic equipment (e.g., CONSULT-III) to accurately pinpoint the problem, especially for wastegate or turbocharger-related issues. Continuing to drive with an underboost condition can lead to reduced engine performance, increased fuel consumption, and potentially more severe engine damage over time. Early diagnosis can save you significant repair costs.

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