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GM recalls 3.8 million vehicles in North America due to braking issue

WASHINGTON — General Motors Co said Wednesday it was recalling 3.46 million U.S. pickup trucks and SUVs to address a vacuum pump issue that could make braking more difficult and that has been linked to 113 accidents and 13 injuries. The recall covers 2014-2018 model year vehicles, including some Cadillac Escalade, Chevrolet Silverado, Chevrolet Tahoe, GMC Sierra, Chevrolet Suburban and GMC Yukon vehicles. In late June, GM recalled 310,000 vehicles in Canada for the same issue. GM did not immediately explain why the Canadian recall occurred more than two months before it called back the vehicles in the United States. The recall was triggered because the amount of vacuum created by the vacuum pump may decrease over time, GM told the National Highway Traffic Safety Administration (NHTSA) in documents posted on Wednesday. The NHTSA opened a preliminary investigation into the issue last November, and said it had reports of nine related crashes and two injuries. It provided GM in July with additional field reports that prompted the automaker to open an investigation. GM said it could affect braking in "rare circumstances." The NHTSA said in a statement the "vehicles may experience brake boost failure, which would require increased brake pedal effort, leading to a hard brake pedal feel, and potentially increased stopping distance." GM said dealers will reprogram the electronic brake control module to improve how the system utilizes the hydraulic brake boost assist function when vacuum assist is depleted. GM said the vacuum assist pump, which is lubricated with engine oil that flows into the pump through a filter screen, can in some cases lose effectiveness over time, as debris such as oil sludge can accumulate on the filter screen. GM told NHTSA that prior model years used a different brake assist system design, and vehicles manufactured after 2018 were not equipped with the affected pump design. Separately, GM said on Wednesday it is recalling 270,000 additional U.S. vehicles in three smaller recalls, including 177,000 2018 Chevrolet Malibu cars with 1.5L turbo engines because an error in the engine control module software may result in the fuel injectors being disabled.

GM recalls select Chevy Cruze, Sonic and Buick Verano models over airbag issue

General Motors is recalling certain 2012 Buick Verano, Chevrolet Cruze and Sonic models due to a defect in the driver's airbag system. According to the National Highway Traffic Safety Administration, the airbag has a shorting bar which may contact two internal terminals. If that happens during a crash, the supplemental restraint may not deploy, increasing the risk of driver injury. The recall includes a total of 2,949 units.
GM will contact owners and replace the steering wheel airbag coil at no cost. At this point, it's unclear when the recall will begin, though owners may contact the automaker at 1-800-521-7300 for more information. You may also take a closer look at the full NHTSA notice below.

GM patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging