We purchased a 2020 GMC 2500 HD Denali upgrading from a 2017 Chevrolet 2500hd Duramax. On the 2017 when braking, we could hear and feel the engine exhaust brake. The new 2020 does not seem to decelerate in the same fashion. If the engine brake is not working on the 2020, would we get a check engine light? Thanks.