So I just had my right valve cover gasket replaced a month ago at the dealer about 2 months ago and got a cel today. I started looking around and noticed my oil was incredibly low. I did an oil change and found that they didn’t use a washer so I’ve been slowly leaking oil for the past 2 months only about 3 1/2 q came out. Now a day later the cel is still on (p0021) and now the battery and brake light popped up. Any ideas?

 

Plug in an OBD2 scanner and see what codes it's throwing.

Battery light on usually means your alternator failed.

Brake light on check your fluid level and make sure your parking brake is completely off.