Example of a charge air bypass valve stuck in the open position (plunger fully retraced).
Photo courtesy of Mitchell 1
Example of the charge air bypass valve fully extended (closed position).
This bulletin applies to 2021-2023 Buick Envision vehicles equipped with a 2.0L engine. DTC P0299 may be set as current or in history. The cause may be a possible charge air bypass valve sticking open intermittently.
Remove the charge air cooler air inlet hose adapter from the turbo. Using a borescope, inspect the compressor wheel for signs of damage. If damaged, replace the turbo. If not damaged, use the borescope and inspect the charge air bypass valve for being stuck in the open position. Be sure to use the borescope for inspection, as attempting removal could unstick the valve, causing it to return to a normally closed position.
If borescope inspection reveals a stuck valve, replace the charge air bypass valve, clear DTCs and evaluate.
Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety ofspecialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.
