Ringer, this came out from the post 

https://business.financialpost.com/news/economy/theyre-in-the-final-strokes-canada-and-u-s-make-key-concessions-as-deal-in-sight-sources-say

Canada agreed to a cap on auto exports to the U.S. – of about 40 per cent above current production levels – that would be free of any auto tariffs Trump might impose, the source said. And only vehicles that failed to meet the rules of origin for auto parts agreed to by the U.S. and Mexico would even potentially be subject to the proposed auto tariffs.

The administration officials also did not specify the nature of what they called an accommodation on auto tariffs, but said a side letter detailing it would be released soon.