2021 Subaru Ascent with 31,500 miles. Turbo engine. CEL came on yesterday, disabling all the safe driving features. It’s a lease, terms in early April, so I took it to the dealer. Dealer says it’s not covered by warranty because the oil is dirty, like it hasn’t been changed in maybe 10,000. We’re not great about oil changes because the car has a sensor that tells you when to do it, but there’s no way we’re at 10,000. I’d be surprised if it was over 6,000, and we use only synthetic in that car. They are convinced that it needs a flush & new oil, and it will be fine. After waiting for them to do a flush/cleanup and oil change, which will total $450, they start it up and the CEL comes back. Now they are keeping it overnight, and gave me a loaner. Something about a solenoid? They said they are going to try to make that a warranty issue. Shouldn’t it all be a warranty issue? Of course, I don’t have a receipt for the last oil change that we think was sometime in the Spring. Can I get some advice on how to approach the shop with arguing for warranty coverage for all of it? Thanks in advance.