P0299 on a 2018-2021 Chevrolet Equinox 1.5L Turbo: Check the Charge Air Tube First
JC Landry, ASE Master TechnicianPublished Oct 26, 2026 · Updated Oct 30, 2026
P0299 on a 2018-2021 Chevrolet Equinox 1.5L (LYX) means actual turbo boost stays below commanded boost by a calibrated margin for over 3 seconds. Check the charge air cooler outlet tube at the throttle body first, then smoke test turbo to throttle body; in extreme cold, suspect an iced cooler. Expect reduced power; get it diagnosed promptly, since a loose tube or failing turbo part will not fix itself.
Safety first
- If the turbo failed, clean all debris and oil out of the charge air cooler system before fitting the new one.
- Click the oil feed pipe fully home, keep it clear of the V-band clamp, and check for leaks with the engine running.
- Turbo nuts are torque-to-yield; use new ones.
- Keep charge air joints clean and secured; never substitute their special fasteners.
What does P0299 mean on a 2018-2021 Equinox?
P0299 (Engine Underboost) means boost is not reaching what the ECM commanded. The ECM reads actual boost from a three-atmosphere boost pressure sensor between the turbo and the throttle body. Key on engine off, at idle and on deceleration, that pressure equals barometric pressure.
The dual-scroll turbo's spring-closed wastegate opens on actuator pressure fed by a PWM wastegate regulator solenoid valve: 100 percent holds it shut, 65 to 80 percent is typical at mid and upper rpm, and 0 percent leaves mechanical boost. A bypass valve opens on closed-throttle deceleration to stop surge and closes under load.
The ECM sets P0299 when actual boost runs below desired by a calibrated amount for more than 3 seconds. The test runs continuously once either of two condition sets holds. Both need the fix-first codes in the diagnosis section clear (MAP sensor codes aside; P2261 applies to the open loop set only), plus:
- Barometric pressure 60 to 120 kPa (8.7 to 17.4 psi)
- Coolant temperature -40 to +126°C (-40 to +259°F)
- Intake air temperature -40 to +80°C (-40 to +176°F)
- Bypass valve not under scan tool output control
- In closed loop boost control, 1,500 to 6,500 rpm with desired boost of 140 to 240 kPa (20.3 to 35 psi)
- In open loop boost control, 2,000 to 3,500 rpm
It is a Type A code: the ECM lights the check engine light on the first failure and stores Freeze Frame/Failure Records; the Service Vehicle Soon light may come on.
Three related codes share this hardware and logic.
- P0234 (Engine Overboost), Type A, same conditions, sets when actual boost exceeds desired by a calibrated amount for more than 3 seconds.
- P0236 (Turbocharger Boost Sensor Performance), Type C, with P0237 and P0238 for circuit low and high voltage. P0236 sets when the sensor disagrees with the ECM's model, or, engine stopped, reads below 44 kPa (6 psi) or above 115 kPa (16.7 psi), or differs from MAP and BARO by more than 10 kPa while they agree within 10 kPa.
- P2261 (Turbocharger Bypass Valve Stuck), Type C, sets on induction pulsations above a calibrated threshold after an abrupt throttle close.
What symptoms does P0299 cause on the Equinox?
- Check engine light on
- Reduced power or a reduced engine power message
- A possible Service Vehicle Soon light
- The code setting during or after extreme cold driving
- A loud thump under acceleration, then limp mode, when the charge air pipe blows off the throttle body
What causes P0299 on the Equinox, most likely first?
I would start with the charge air path.
| Rank | Cause | Quick confirm | Typical fix |
|---|---|---|---|
| 1 | Charge air leak, or cooler outlet tube off the throttle body | Check the throttle body joint, then smoke test | Reseat with a new retainer, or replace the tube if damaged or the O-ring is missing; repair cracked ducts |
| 2 | Iced charge air cooler (extreme cold only) | Sets in extreme cold with a clean leak check | Thaw and wash the cooler, shutter or grille cover, ECM reprogram |
| 3 | Wastegate solenoid valve stuck, frozen or contaminated | Command it, then run the vacuum bleed-off test | Clean and wrap in cold weather cases, or replace |
| 4 | Wastegate actuator, hose or linkage | Pressurize the actuator, watch the rod | Repair the hose, replace the actuator, or the turbo if the wastegate binds |
| 5 | Bypass valve solenoid not closing | Command it and watch the plunger | Replace the solenoid |
| 6 | Exhaust leak ahead of the turbo, or restriction | Inspect the exhaust | Repair it |
| 7 | Turbo internal damage | Inspect blades, passages, wastegate | Clean the cooler system, replace the turbo |
GM service bulletin 22-NA-224 covers the outlet tube separating from the throttle body (cause 1), and GM service bulletins 18-NA-020 and 22-NA-002 cover cold weather underboost (causes 2 and 3).
How do you diagnose P0299 on a 2018-2021 Equinox?
You need a scan tool with output controls, hand tools, a hand vacuum and pressure pump, and a smoke machine or soapy water.
Diagnose these first if stored:
- MAP sensor, P0106 through P0108
- Boost pressure sensor, P0236 through P0238
- BARO sensor, P2227 through P2230
- Wastegate solenoid circuit, P0243, P0245, P0246
- Bypass valve solenoid, P0033 through P0035, and bypass valve stuck, P2261
- Intake air temperature sensor, P0111 through P0114
- Coolant temperature sensor, P0116 through P0119 and P111E, and P0128 (coolant below thermostat temperature)
- 1
Check the pressure sensors.
Key on, engine off, BARO should suit your altitude, and MAP and boost should each sit close to BARO. If BARO is off, diagnose P2227 through P2230; if MAP disagrees, P0106; if boost disagrees, P0236. That proves the ECM reads pressure correctly.
- 2
Command the turbo solenoids.
The bypass valve solenoid should click between active and inactive with no Malfunction in its circuit status; if not, diagnose P0033 through P0035. From 5 to 95 percent, the wastegate solenoid's clicks should speed up, with no Malfunction; if not, diagnose P0243, P0245 or P0246.
- 3
Road test.
Compare MAP and boost on a wide open throttle pull through the 1-2 shift; if far apart, go straight to the inspection. Otherwise drive within the conditions above or those stored in Freeze Frame/Failure Records. If P0299 resets, inspect; if not, the system checks out.
- 4
Inspect the air and exhaust path.
First confirm the cooler outlet tube is on the throttle body. If not, inspect the tube, clip and throttle body; replace the tube if its end is damaged or the O-ring missing, and the throttle body or MAF sensor only if damaged or confirmed as the cause. If attached, look for loose clamps or retainers, cracked, collapsed or restricted ducts, a restricted air filter, charge air leaks, split, kinked or misconnected vacuum hoses, bad or misrouted wastegate hoses, missing, restricted or leaking exhaust parts (including turbo to manifold), a restricted or leaking turbo oil supply line, and loose or misinstalled parts. Pinpoint leaks with smoke or soapy water and repair them.
If it set at -18°C (0°F) or colder with a clean leak check, switch to GM's cold weather procedure. Drain the wastegate solenoid upside down, blow regulated shop air through its ports, replace it only if the plunger is stuck, and fit the thermal wrap where it applies. Wipe the boost sensor dry with a clean rag, no chemicals, then smoke test. A frozen or contaminated, non-leaking cooler gets thawed, washed and refitted; replace it only if built before 03/01/2018 and never replaced. Add the lower cooler shutter, a soft grille cover in rare cases (removed once temperatures average 0°C (32°F) or above) and an ECM reprogram. Leave undamaged, leak-free cooler ducts alone.
- 5
Test the wastegate control.
Apply vacuum to the compressor-inlet-to-solenoid hose at the turbo and command the solenoid to at least 15 percent; the vacuum should bleed off completely. If not, replace the solenoid (outside an extreme cold case). Reconnect, then pressurize the actuator; the rod should move. If not, disconnect the actuator arm and retry: still no movement means a new actuator, movement means the wastegate binds and the turbo is replaced.
- 6
Test the bypass valve and inspect the turbo.
With the solenoid removed but plugged in, command it; the plunger should retract and extend, or the solenoid gets replaced. Inspect the turbo for cracked, damaged or worn blades, restrictions in the wastegate, turbine, ports or passages, or foreign material, and repair or replace as needed. PCV fluid and combustion buildup on the compressor and turbine is common and not a sign of failure. If nothing turns up, the turbo gets replaced.
Get the P0299 tests for your Equinox
The charge air tube check, solenoid commands and wastegate tests above follow GM's own test order. Ask emanuals.ai about your Equinox 1.5L and get the exact test steps, specs and procedures from the factory manual.
Specs you need for the Equinox P0299 repair
| Turbo nuts (new, in sequence) | 15 N.m (11 lb ft), 20 N.m (15 lb ft), then 60 degrees |
|---|---|
| Oil feed pipe fitting, coolant feed pipe hollow screw | 35 N.m (26 lb ft) |
| Oil feed pipe bolt | 32 N.m (24 lb ft) |
| Oil return pipe bolts, heat shield, wastegate actuator | 10 N.m (89 lb in) |
| Bypass valve solenoid, charge air cooler and bracket bolts | 9 N.m (80 lb in) |
| Wastegate solenoid valve bolt | 8 N.m (71 lb in) |
| Boost sensor bolt | 3.8 N.m (34 lb in) |
| Coolant | DEX-COOL 50/50, 6.6 L (7.0 qt) |
| Engine oil | SAE 0W-20 dexos1 Gen 2 |
What if the obvious fix does not work?
If the code returns after reseating the tube, keep going; a second leak or bad wastegate hose can still hold boost down. In cold weather a clean smoke test does not clear the cooler, because ice blocks airflow without leaking. A clogged catalytic converter can also cause it, and an oily throttle body joint may just be crankcase vapor from the cooler.
Do not replace the turbo before checking pipes, cooler and leaks, and never skip the learned values reset.
Stop once the sensors agree, the solenoids and actuator pass, the path is tight and the turbo inspection finds nothing. Then the turbo gets replaced, after cleaning debris and oil out of the charge air cooler system.
How do you confirm the repair?
The Intake System Learned Values Reset is required after servicing or replacing the boost, MAP or MAF sensor, throttle body, either turbo solenoid or the turbo, or fixing a collapsed, leaking, loose or restricted intake duct. Run it with the scan tool, engine off, ignition on.
A new boost sensor gets a new seal lubed with clean engine oil. A turbo job means a coolant drain and refill; afterward, run the engine and check the connections for leaks.
Clear codes with the ignition on, then switch off for over 60 seconds. MAP and boost should agree on a wide open throttle pull through the 1-2 shift. Drive at 1,500 to 6,500 rpm with desired boost of 140 to 240 kPa (20.3 to 35 psi), or 2,000 to 3,500 rpm, without P0299 setting; Freeze Frame/Failure Records help recreate the original conditions.
Questions mechanics ask about P0299 on the Equinox
Can you drive an Equinox 1.5L with P0299?+–
Expect reduced power with this code, and the check engine light comes on the first time the test fails. Get it diagnosed rather than driving on it, because a loose charge air tube or a failing turbo part will not fix itself.
Will P0299 clear itself on the Equinox?+–
The light goes off after 4 consecutive ignition cycles where the test runs and passes. The stored history code clears after 40 consecutive warm-up cycles with no emission fault. A scan tool can clear it once the repair is made.
What other codes set with P0299 on the 1.5L Equinox?+–
P0234 is its sibling on the same boost test. GM's service bulletin 22-NA-224 pairs P0299 with P0101, P0172, P0506 and P1101 when the charge air cooler outlet tube comes off the throttle body. Service bulletin 18-NA-020 pairs it with P0300 and P2227 when the charge air cooler ices up in extreme cold.
Why does P0299 show up in winter on the Equinox 1.5L?+–
Moisture from outside air and crankcase vapor can collect and freeze in the charge air cooler in extreme cold, restricting airflow. GM's cold weather procedure applies only when the code is tied to temperatures of -18°C (0°F) or lower, and leaks get ruled out first.
Does GM's coverage pay for the cold weather P0299 fix on the Equinox?+–
GM covers the ECM reprogram for cold weather P0299 on the LYX for 8 years/80,000 miles in the U.S. (8 years/130,000 km in Canada). That reprogram comes from service bulletin 22-NA-002 and uses overdrive less in cold weather, so highway rpm can run higher. Other repairs fall under the vehicle's Powertrain coverage, which a GM dealer checks in Investigate Vehicle History.
Sources
- Chevrolet Equinox Service & Repair Manual, section Engine Controls and Fuel, 1.5L (LYX), DTC P0234 or P0299 (1.5L LYX engine).OEM Manual
- Chevrolet Equinox Service & Repair Manual, section Engine Mechanical, 1.5L (LYX), Turbocharger Replacement and Installation (1.5L LYX engine).OEM Manual
- GM service bulletin 18-NA-020, "Poor Engine Performance in Extremely Cold Weather Conditions, Malfunction Indicator Lamp (MIL) Illuminated with DTCs P0300, P0299, P0234 and/or P2227 Set", 2018-2024, May 2024.Service Bulletin
- GM service bulletin 22-NA-002, "Malfunction Indicator Lamp Illuminated with DTCs P0299/P0234 Set During Cold or Freezing Temperatures", 2018-2022, February 2022.Service Bulletin
- GM service bulletin 22-NA-224, "Reduced Engine Power, Malfunction Indicator Lamp (MIL) Illuminated - DTC’s P0101, P0172, P0299, P0506 and/or P1101 Set", 2018-2022, November 2022.Service Bulletin
- emanuals.ai, Query data, "P0299 Chevrolet Equinox".First-Party Data
ASE Master Technician
JC spent 15+ years as a certified Master Mechanic before trading the shop for the keyboard. He's worked across dealerships, owned and operated his own independent garage, and consulted on automotive trade school curricula, reviewing technical textbooks used in vocational programs.
He now serves as Editor-in-Chief at emanuals.ai, where he oversees the platform's technical content. He's one of the few voices in automotive publishing who turned wrenches professionally for decades before he had a byline.
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