$7E8, 7E9 and loose gas cap lights?

The "loose gas cap" light is a separate warning related to the evaporative emissions system. It's designed to alert you if the gas cap is not properly tightened or if there is a leak in the system.

Thank you, Ken. I will have a chance to run the reader again this weekend and hope for more data. My gas cap placement has been impeccable since this started, clean connections and audible clicks... :-) Never have I thought more about closing a gas cap!

Yep, the system needs to be sealed to work correctly. :) have a good weekend.

Well, I took it to a professional and I have a "cracked canister," a $355. part. Now hoping the "b-b like pellets" inside haven't been sucked into the system. (Code reader leaves the mechanic feeling optimistic...) I wish this made sense to me, but the difference between working on a 2017 Mazda and a 1972 VW van is making me feel old.

Yep, it happens, here is how the canister is replaced in case you want to do the job, thanks for letting us know what was wrong. Check out the images (below). Please let us know what happens.

Thanks so much. I'll let the pros earn their $120 and get it done in an hour! While learning about this, could you point me to a primer on how this system works? BBs in the canister??!

Sure, here is how the EVAP system works and illustrations to help with the explanation. Use 2CarPros anytime, we are here to help. Please tell a friend.