The automakers will report September vehicle sales on Monday, October 3rd.

Note:  There were 25 selling days in September, the same as in September 2015.

From WardsAuto: Forecast: U.S. SAAR to Rebound in September

The forecast 17.6 million SAAR is greater than 16.9 million from prior-month and the 17.2 million over the first eight months of the year.
emphasis added

This graph shows light vehicle sales since the BEA started keeping data in 1967.

Vehicle SalesThe dashed line is the August sales rate.

Sales for 2016 – through the first eight months – were up slightly from the comparable period last year.

After increasing significantly for several years following the financial crisis, auto sales are now mostly moving sideways.