I have an Air Canada ticket from BWI to Heathrow via Toronto Pearson. Do I need to recheck my bags and must I go through Customs in Toronto? If so, will 1.5 hour suffice?
No need to grab & recheck the bags, but you have to fill out your Canadian customs declaration card and go through immigration/customs. 1.5 hours should be fine unless there is a total mess at immigration.
Minimum connection time for this would be 60 minutes. See https://www.aircanada.com/us/en/aco/home/plan/check-in-information/minimum-connection-times.html
You should probably read through this web page. It has all the information you need. To specifically answer your questions:
- No, you will not need to recheck your bag
- Yes, you need to go through Canadian CBP, but (assuming you have a US passport), that will be no problem
- I've never been to Toronto Pearson Airport but that seems tight to me.