P0299: Turbocharger/Supercharger A Underboost Condition
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - the car will feel slow and may enter limp mode on hills.
Symptoms
- Noticeably reduced power
- Limp mode under load
- Whistling or hissing from the engine bay
Likely causes, most common first
- Boost leak at a hose, clamp or intercooler
- Wastegate stuck open or actuator worn
- Turbocharger worn or damaged
- Clogged air filter or restricted intake
Read P0299 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0299 is the opposite of P0234: the engine asked for boost and did not get it. On downsized turbocharged engines this is one of the most frequently reported codes, and most of the time the turbocharger itself is innocent.
Pressurised air escapes long before a turbo wears out. Charge pipes, silicone couplers, clamps and intercooler seams all leak with age and heat cycling, and a leak large enough to set the code is often audible as a hiss under acceleration. A smoke test of the charge system finds it in minutes and saves a great deal of money compared with replacing the turbocharger on suspicion.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0299
“car in question is a 2022 Audi q7 55 tfsi - 3.0 turbo - 40k miles 2 owner. serviced at Audi since new. under warranty until 50k car throws a p0299 code - turbo underboost condition present - coolant migration from a faulty VW/AUDI water pump is sending coolant into vacuum lines causing catastrophic engine issues - car can not be driven. Audi will not fix under warranty and is trying to charge 5,800$ to replace waterpump/ associated lines. tells me the warranty "is for some items and not others" there is a class action lawsuit for a longstanding issue that Audi has been aware of since 2020 and not offering any solution for - Case No. 26-5678, NJ.”2022 Audi Q7 · Jul 2026
“The turbo charger. The vehicle is currently at the dealership where it was made known that many other similar vehicles are experiencing this issue with no cause. The vehicle has been inspected by the dealer. This issues occurred 1 week ago. All the warning lights came up out of no where. Took it to two different places where they confirmed it was code P0299.”2018 Honda Accord · Jun 2026
“The contact owns a 2022 Chevrolet Malibu. The contact stated that while driving approximately 62 MPH, the vehicle lost motive power with the message "Reduced Engine Power" displayed, and the check engine warning light intermittently illuminated. The vehicle was taken to an independent mechanic, where a diagnostic scan retrieved DTC: P0299, indicating a failure with the turbo charger. The vehicle was then taken to the local dealer, who confirmed that the vehicle was not eligible for the GM Special Coverage: N252508360. The manufacturer was not notified of the failure. The failure mileage was approximately 82,010.”2022 Chevrolet Malibu · May 2026 · 82,010 mi
Show 7 more owner reports
“My engine keeps decreasing and throwing code p0299, wastegate/turbo, under boost. 84k miles. After a few drive cycles, engine light may go off, then next drive cycle come back on. I’ve seen this is a common issue and has been recalled in previous year model.”2023 Chevrolet Malibu · Mar 2026
“The turbo! Code P0299! Hundreds of thousands of Americans going through the same issue all their lights are flashing on their dashboard with these 1.5 T engines”2019 Honda Accord · Mar 2026
“2020 Buick Encore GX; pulling out of a service station, my check engine light illuminated, and message on cluster stated: Engine Power Reduced. I loss throttle response for accelerating. Accelerator pedal was pushed to the floor and no acceleration. Vehicle entered limp mode. Drove 15 miles from service station to my home, in limp mode, unable to accelerate. Called a technician mechanic who check for Diagnostic Trouble Codes; DTC P0299 Turbocharge/Supercharge "A" Under boost condition; is Confirmed, Pending, and Permanent code. Loss of power to Power Train, unable to accelerate.”2020 Buick Encore GX · Feb 2026
“Vehicle was taken to dealership feb 2026 for turbo/wastegate repair (p0299). March 22, 2026, vehicle stalled and screen said to shift to neutral and push to start again. Car would crank but not start (sounds like there is no compression). Had vehichle towed two miles to residence and connected to obdii scanner, which showed 6 new codes (p0006, p228c, p0089, p0340, p0365, p0299).”2021 Chevrolet Trailblazer · Feb 2026
“The turbocharger gave code P0299 then more extensive look when you try to increase speed the turbo will not boost to allow you to go. 40-45 miles is the highest you can go . Dealership said there we complaints and recalls. The recalls are for 2017 and 2018 chevy trax. 2019 having the same issue..”2019 Chevrolet Trax · Feb 2026
“Turbo exhibits exact same symptoms of 17-18 encore recall for the turbo. I frequently get the p0299 code the car becomes sluggish and hesitates to take off from a stop when this code comes on making this car dangerous to drive. This issue has almost caused multiple accidents because the car is so under powered that its hard to get the car across traffic without being hit. I have been having this issue for several years and no one has been able to tell me why the car does this.”2016 Buick Encore · Jan 2026
“SUVs check engine light turned on and went into reduced power mode, it has been very cold for approximately a month. Code P0299.”2022 GMC Terrain · Jan 2026
Cars that report P0299 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0299?
Yes - the car will feel slow and may enter limp mode on hills.
How much does it cost to fix P0299?
Typical US repair costs range from $60 for the simplest fix (boost hose or clamp) to $3,500 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0299. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.