Hello, the error code 84 appeared in my workshop after just under 1000km. Time: Speeding up to top speed. Car ran on it in the emergency program up to max. 100km/h. The car was then 5 weeks in the workshop. The following repair tests were carried out: 1. Software update 2. Replacement turbocharger 3. Exhaust gas return valve checks everything nothing! So, and now the success: An intake hose in front of the turbocharger was fixed with cable ties on the cooler. The error no longer occurs! Explanation: Due to high temperature and the strong air flow said hose is deformed. The hose cross-section decreases and the turbo virtually lacks the required air at the highest power query. This apparently detects a sensor and switches in the emergency run program for the sake of caution… Why I write all this? In Bremen stands at Chevy about 70! Orlando Diesel with the same error code and the Chevy’s have no plan what it might be! My workshop has done excellent work here! And Chevrolet apparently brings a car to the market, which has never been tested at maximum speed – a poverty certificate in 2012! Maybe Chevy.