Your 2007 GMC Yukon Denali will be administered a 2 speed idle test as opposed to the ASM (accelerated simulation) test. The during the 2 speed idle test your Yukon Denali will not be driven on a dynamometer. All other aspects of the smog check will be the same as if your Denali was a 2 wheel drive except the exhaust emissions sampling portion. During this portion of the test the smog machine will take a sample of your Yukon Denali's exhaust once at idle (for 30 seconds) and once at 2500 rpm (for 30 seconds).
