P0299 Chevy Trax: Meaning, Causes & Fix

P0299 means "Turbocharger/Supercharger 'A' Underboost Condition" — the engine control module commanded a certain amount of boost, compared it against what the manifold pressure sensor actually reported, and found the turbocharger falling short. On a Chevrolet Trax the important thing to know up front is that GM issued a bulletin warning technicians not to replace the turbocharger for this code before ruling out the cheaper causes, because too many turbos were coming back with no fault found. There is also a two-minute inspection with your fingers that tells you whether the turbo is genuinely the problem.

What Does P0299 Mean on a Chevy Trax?

The ECM knows how much boost it asked for. It reads actual manifold pressure from the MAP sensor and compares. When actual pressure sits meaningfully below target for a sustained period — commonly described as a few PSI short for several seconds — P0299 sets and the vehicle usually drops into reduced power.

The critical point is what that comparison does not tell you. The code says boost did not arrive. It does not say why. On a small turbocharged engine, pressurised air can go missing at many points between the turbo and the cylinders, and the turbocharger itself is only one of them — and by far the most expensive.

GM's own field experience makes this concrete. PIP5495N was issued to warn technicians about exactly this pattern: P0299 leading to turbocharger replacements that did not fix the car, with turbos being returned as no-trouble-found. The bulletin directs ruling out the PCV system, boost leaks, wastegate control and charge air cooler icing first.

So if a shop has quoted you a turbocharger on the strength of this code alone, that bulletin is worth raising.

Which Engine Does Your Trax Have?

The Trax has had three quite different powertrains, and the P0299 story differs across them.

Years	Engine	Where to look first
2013–2016	1.4L turbo, RPO LUJ / LUV (port injected)	Wastegate preload, PCV system check valves, intake manifold. The most documented generation
2017–2022	1.4L turbo, RPO LE2 (direct injected)	Wastegate regulator solenoid, cold-weather icing, boost leaks
2024 onward	1.2L turbo three-cylinder, RPO LIH — an entirely new vehicle	Standard boost-leak diagnosis; the older bulletins do not apply

Note there is no 2023 Trax in the US — the first generation ended after 2022 and the redesigned model arrived for 2024. If a page offers you "2013–2024 Trax" advice as one block, it is describing two unrelated vehicles.

Most P0299 complaints come from the first generation, and that is where GM's documentation is richest.

The Two-Minute Wastegate Test

This is the most useful thing on the page, it comes from a GM bulletin, and it costs nothing.

PI1366 (December 2014) covers 2013–2015 Chevrolet Trax and Sonic, 2011–2015 Cruze and 2013–2015 Buick Encore with the 1.4L LUJ or LUV engine. Its subject is precisely our topic: MIL illuminated due to DTC P0299, loss of turbocharger boost.

GM's stated cause is loss of wastegate preload. And GM makes a distinction that matters: some wear in the wastegate actuator rod end to pin joint is normal. Wear in this joint does not affect performance and does not set any codes as long as preload is maintained. In other words, a bit of play is not automatically a fault — the preload is what counts.

The inspection GM publishes:

1. Remove the exhaust manifold heat shield. GM warns not to service the exhaust while hot — let it cool first.
2. Check the retention clip is in place. If it is missing, fit a new clip. This alone is a known and very cheap fix.
3. Wiggle the wastegate pivot lever back and forth with your fingers.
4. Read the result: if the lever wiggles with little effort while the actuator rod stays still, preload is insufficient.
5. Failed inspection means the turbocharger is replaced. Passed inspection means continue diagnosis elsewhere.

That is a genuine pass/fail on the expensive part, done with your fingers. It is the test that separates "the turbo really is finished" from "the turbo is fine and something else is losing boost" — which is the entire question this code raises.

Two further wastegate-related documents are reported in GM's preliminary information: PIP6058A, noting P0299 may set due to wastegate binding, and field reports of a worn pivot pin on the internal wastegate arm allowing exhaust to bypass the turbine — a mechanical fault a smoke test cannot find, since nothing is leaking.

The PCV Failure That Fakes a Bad Turbo

On the first-generation 1.4L, this is the cause that catches the most people, and the mechanism is worth understanding because it explains why a smoke test can come back clean.

The crankcase ventilation system on these engines uses a diaphragm integral to the camshaft cover and a check valve inside the intake manifold. When either fails, boost pressure gets a path from the intake manifold back toward the turbo inlet. That is an internal boost leak — pressure escaping inside the engine rather than out of a split hose — so the pressure never reaches the cylinders and the ECM sees underboost.

We have a verified GM document tying this family of failures together on the Trax. PIP5197H covers 2013–2019 Chevrolet Trax (along with Encore, Cruze and Sonic) with the 1.4L LUJ and LUV engines, under the title "Possible Oil Consumption — Oil Leaks — Blue Smoke From The Exhaust — Whistle Noise — MIL On — DTC P0171." Critically, GM states: any or all of the following DTCs may be current or set in history: P0171, P0300 or P0299.

So GM itself puts P0299 in the same document as the PCV orifice diaphragm failure. The bulletin's inspection steps:

• Check the oil fill cap and dipstick for proper sealing — free, and first on GM's list.
• Check the PCV orifice for leaking oil or drawing vacuum at idle through its external port. GM notes the orifice is an integral part of the camshaft cover. If that port is leaking oil or vacuum, replace the camshaft cover assembly.
• Check for a missing intake manifold non-return valve, which can damage the PCV orifice diaphragm. If it is missing, replace the intake manifold. If it is present, reinstall it — do not replace it.
• Record crankcase pressure. GM's normal range for these engines is −11 to −18 inches of water at hot idle in park, measured with the tester connected at the dipstick hole with the engine off, then started.

GM adds a reading for that measurement: a result between −10 and 0 inches of water indicates a cylinder leakage or crankcase pressure concern, likely a weak or broken piston ring land, and GM's instruction there is to replace all four piston assemblies.

There is a well-known shortcut owners use for the same thing: at idle, try to lift the oil fill cap. Abnormally strong suction holding it down points at the crankcase ventilation system. It is not a substitute for the gauge, but it is free and it will tell you whether this path is worth pursuing.

One practical note from the field: the intake manifold check valve on these engines is a known weak point, and redesigned aftermarket manifolds exist specifically to address it. Whether you go OE or otherwise, the point is that the manifold can be the underboost repair.

Cold Weather — Solenoid Freezing and Intercooler Ice

If your Trax sets P0299 in winter, or on the first genuinely cold morning of the year, read this before buying anything.

PIP5812C is reported to document oil and moisture freezing inside the turbocharger wastegate regulator solenoid valve in cold weather, setting P0299. The solenoid is an inexpensive part relative to a turbocharger, and this is described as the leading cause on the later 1.4L LE2 Trax in cold climates.

Separately, 17-NA-221 is reported to cover ice building up inside the charge air cooler — the intercooler — restricting airflow and setting P0299. Small-displacement turbo engines are particularly prone to this because condensation collects in the cooler and freezes.

The pattern to look for: the code appears in cold weather, power is down, and after the vehicle sits warm somewhere it behaves normally again for a while. That is ice, not a failed turbocharger, and the fix is nothing like as expensive.

This is the same family of cold-weather charge-air behaviour we documented on the newer 1.5L in our P0299 Equinox guide, where GM published a full moisture-and-ice repair chart.

We could not open PIP5812C or 17-NA-221 ourselves. Multiple technician-facing sources describe both consistently, so we report them as corroborated rather than as verified GM wording. The documents we read directly are PI1366 and PIP5197H.

What the Companion Codes Tell You

P0299 rarely arrives alone, and what sits alongside it narrows the diagnosis considerably.

Alongside P0299	What it points at
P0171 (system too lean)	Unmetered air or a PCV failure. GM lists P0171 and P0299 in the same bulletin for this engine — see our P0171 guide
P1101 (intake air flow system performance)	Strongly suggests a boost or vacuum leak, or crankcase ventilation trouble — see our P1101 guide
P0300 (random misfire)	GM lists this with P0299 on this engine. Can indicate a weak or broken piston ring land
P0234 (overboost)	Points at wastegate control rather than a leak — the wastegate is not regulating in either direction
P0299 alone, cold weather only	Wastegate solenoid freezing or charge air cooler icing
P0299 alone, all conditions, no leaks found	Wastegate preload — do the PI1366 finger test

Symptoms of P0299 on a Trax

• Check engine light on
• Significantly reduced power, especially merging, overtaking or climbing — this is the one owners notice
• Reduced Engine Power message, or the vehicle entering limp mode
• Sluggish acceleration that feels like the turbo simply is not there
• Poor fuel economy
• A whistling or hissing noise under acceleration, suggesting escaping pressurised air
• Symptoms that appear only in cold weather and clear once things warm through
• Oil consumption or blue smoke alongside the code, pointing at crankcase ventilation

The power loss makes this more than an inconvenience. Merging onto a highway in a vehicle that will not accelerate is a genuine safety issue, which is a reasonable argument for getting it diagnosed promptly rather than living with it.

What Causes P0299 — and How Do You Confirm Each One?

Cause	How to confirm it	Source
Missing wastegate actuator retention clip	Remove the heat shield (cold) and look. GM's step 2	PI1366
Loss of wastegate preload	Wiggle the pivot lever by finger. If it moves easily while the actuator rod stays static, preload is insufficient	PI1366 — verified
Wastegate binding or worn internal pivot pin	Will not show on a smoke test — nothing is leaking. Suspect where leaks are ruled out and preload is marginal	PIP6058A, field reports
PCV orifice diaphragm failure in the camshaft cover	Check the external port for leaking oil or drawing vacuum at idle. Strong suction at the oil fill cap is the free version	PIP5197H — verified
Missing intake manifold non-return valve	Inspect; wipe excess oil with a long swab. If still not visible, manifold removal is needed to confirm	PIP5197H — verified
Split or disconnected charge air ducting	Pressurised smoke test of the charge air system. Check clamps and the connection at the turbo	PIP5927D reported for the charge air inlet pipe at the turbo
Wastegate regulator solenoid freezing	Cold-weather-only pattern that clears when warm	PIP5812C — corroborated
Ice in the charge air cooler	Same cold-weather pattern; inspect the intercooler and its plumbing	17-NA-221 — corroborated
Weak or broken piston ring land	Crankcase pressure between −10 and 0 inches of water against a normal range of −11 to −18	PIP5197H — verified
Restricted air intake or dirty filter	Inspect the filter, housing and ducting for restriction	Cheap to rule out
Genuinely failed turbocharger	Only after the above. Shaft play, oil in the ducting, noise change, failed preload test	PIP5495N warns against reaching here first

How Is P0299 Diagnosed?

1. Record every stored code. P0171, P1101, P0300 or P0234 alongside changes the direction entirely — see the table above.
2. Establish when it happens. Cold weather only is a completely different diagnosis from all conditions.
3. Try lifting the oil fill cap at idle. Strong suction implicates the crankcase ventilation system. Free.
4. Check the oil fill cap seal and dipstick seating — GM's first step in PIP5197H.
5. Inspect the charge air ducting from turbo to throttle body for splits, loose clamps and oil residue, including the connection at the turbo itself.
6. Smoke test the charge air system under pressure to find external boost leaks.
7. Do the wastegate inspection from PI1366 — heat shield off with the exhaust cold, verify the clip, wiggle the pivot lever.
8. Check the PCV orifice port for leaking oil or drawing vacuum at idle, and inspect for the intake manifold non-return valve.
9. Measure crankcase pressure against −11 to −18 inches of water for this engine family, connecting with the engine off and then starting it.
10. Compare desired against actual boost on a scan tool during a road test, and only then consider the turbocharger.

Steps 3 and 7 are the two that most often end the diagnosis, and neither costs anything but time.

Parts and Cost

Repair	What it involves	Cost picture
Wastegate retention clip	A small clip GM tells technicians to check for and fit if missing	Close to nothing — and a documented fix
Oil fill cap or dipstick seal	Seating or replacing a cap	Minimal
Charge air duct or clamp	Single hose or clamp replacement	Modest; realistic DIY
Wastegate regulator solenoid valve	The cold-weather freezing part. Order by VIN — the LUJ/LUV and LE2 use different solenoids and the numbers do not cross	Inexpensive relative to a turbo
Camshaft cover assembly	Where the PCV orifice port leaks oil or vacuum	Moderate — GM's stated correction, not a guess
Intake manifold assembly	Only where the non-return valve is confirmed missing	Higher; confirm before ordering
Turbocharger	Where the preload test fails or the unit is physically damaged	The large one — and the one PIP5495N exists to prevent buying prematurely
Piston assemblies	Where crankcase pressure indicates a ring land failure	Major engine work; confirm with the gauge first

A note on that solenoid: part numbers differ between the first-generation LUJ/LUV engine and the later LE2, and fitting the wrong one is a documented mistake. Order against your VIN rather than a model-year listing.

GM Documents Behind P0299 on the Trax

Document	Date	Subject	Coverage
PI1366	Dec 2014	MIL due to P0299, loss of turbocharger boost — loss of wastegate preload. Full inspection procedure with pass/fail criteria. Replaces PIP5023A	Trax and Sonic 2013–2015, Cruze 2011–2015, Encore 2013–2015, 1.4L LUJ / LUV
PIP5197H	2018	Oil consumption, oil leaks, blue smoke, whistle noise, MIL on — P0171, and GM notes P0300 or P0299 may also be set. PCV orifice, intake manifold non-return valve, crankcase pressure spec	Trax 2013–2019, Encore 2013–2019, Cruze 2011–2016, Sonic 2012–2019, 1.4L LUJ / LUV
PIP5495N	—	Warns against replacing the turbocharger for P0299 before ruling out PCV faults, boost leaks and charge air cooler icing; notes turbos returned with no trouble found	1.4L turbo — corroborated, not opened
PIP5812C	—	Oil and moisture freezing in the turbocharger wastegate regulator solenoid valve in cold weather	Corroborated, not opened
17-NA-221	—	Ice build-up in the charge air cooler restricting airflow	Corroborated, not opened
PIP5927D / PIP6058A	—	Damaged charge air inlet pipe connection at the turbocharger; wastegate binding	Corroborated, not opened

What Other P0299 Pages Get Wrong

• Treating P0299 as "your turbo is bad." GM issued PIP5495N precisely because that assumption was producing replacements that did not fix the vehicle, with turbos returned as no trouble found. The code reports missing boost, not a failed component.
• Never mentioning the wastegate preload test. PI1366 gives a finger test with a clear pass/fail on the most expensive part in the diagnosis, and it names the Trax by model year. It costs nothing and almost nobody publishes it.
• Missing that a smoke test can pass with a real fault present. A PCV diaphragm failure leaks boost internally, and a worn wastegate pivot lets exhaust bypass the turbine. Neither shows as an external leak. "It passed a smoke test" does not clear the turbo or the PCV system.
• Lumping all Trax years together. The 2013–2016 LUJ/LUV, the 2017–2022 LE2 and the 2024-onward 1.2L three-cylinder are different engines in two different vehicles, with different likely causes and different parts. There is no 2023 model year in the US.
• Ignoring the cold-weather pattern. A code that appears in winter and behaves when warm points at solenoid freezing or intercooler ice, not at a worn turbocharger.
• Quoting one solenoid part number for every 1.4L. The first-generation and second-generation engines use different wastegate solenoids and the numbers do not interchange. Order against the VIN.

We publish specifications, procedures and vehicle coverage only where we could read them in GM's own documentation — here, PI1366 and PIP5197H — and we say plainly where we are relying on corroborated secondary sources instead.

Frequently Asked Questions

Can I keep driving my Trax with P0299?

It will usually run, but with significantly reduced power and often in limp mode, which is a real safety concern when merging or overtaking. Beyond that, if the cause is a failing PCV system, continuing to drive can force oil past engine seals and turn a moderate repair into a larger one. Get it diagnosed rather than adapting to it.

Does P0299 always mean the turbocharger has failed?

No, and GM says so. PIP5495N was issued to stop technicians replacing turbochargers for this code before ruling out PCV faults, boost leaks, wastegate control and charge air cooler icing — because too many replaced turbos were coming back with no fault found.

What is the wastegate preload test?

From GM bulletin PI1366: with the exhaust cold, remove the heat shield, confirm the retention clip is in place, and wiggle the wastegate pivot lever with your fingers. If the lever moves with little effort while the actuator rod stays still, preload is insufficient and GM's instruction is to replace the turbocharger. If it passes, keep diagnosing elsewhere. GM also notes some wear at the rod end to pin joint is normal and sets no codes as long as preload holds.

Why does my Trax only set P0299 when it is cold?

Two documented reasons on these engines: oil and moisture freezing inside the turbocharger wastegate regulator solenoid valve, and ice building up inside the charge air cooler and restricting airflow. Both are far cheaper than a turbocharger, and both fit the pattern of a code that appears in winter and behaves once things warm up.

I have P0299 and P0171 together. What does that mean?

That combination points hard at the crankcase ventilation system on the 1.4L. GM's PIP5197H covers the Trax and states that P0171, P0300 or P0299 may all be current or in history, with the PCV orifice in the camshaft cover and a missing intake manifold non-return valve among the causes. Start there rather than at the turbo.

What is the oil cap trick?

At idle, try to lift the oil filler cap. If it is held down by unusually strong suction, the crankcase ventilation system is a strong suspect. It is not a substitute for a proper crankcase pressure reading — GM's normal range on this engine is −11 to −18 inches of water at hot idle — but it is free and takes seconds.

My smoke test came back clean. Does that rule out a leak?

Not entirely. A smoke test finds air escaping to the outside. It will not find a PCV diaphragm routing boost internally back toward the turbo inlet, and it will not find a worn wastegate pivot letting exhaust bypass the turbine. Both cause underboost with nothing leaking externally.

Is this the same engine as the Cruze and Encore?

On the first-generation Trax, yes — the 1.4L LUJ and LUV are shared across the Trax, Sonic, Cruze and Buick Encore, which is why GM's bulletins list them together and why the failure patterns are identical. Our Cruze 1.4L turbo guide covers the more serious end of what can go wrong with this engine family.

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