I have a 2016 S60 with 139,000 miles on it. This morning when I started it is was idling rough with the check engine light blinking and the reduced engine performance message on. I waited a few minutes, shut it off and then restarted it a few minutes after that. No more messages, the car ran fine the rest of the day. I hooked up my code reader and no codes were stored. Anyone have any ideas what it could be?

 

Usually a flashing CEL indicates a misfire. I actually had something similar happen to me where I had a misfire due to a bad coil and it would flash the CEL if I gave it heavier throttle but never actually stored a code. I never checked it with VIDA or checked the modules for anything other than a CEL, but I knew it was the coil based on my previous work with the car. When was the last time spark plugs were replaced? They should be done every 60k miles. Could be a weak spark that was good enough once it warmed up a little bit.

 

do you do much highway driving in your daily routine? A weak coil may only misfire under load (say when accellerating to get onto a highway etc). Last time I had this issue, I drove my car fairly agressively on the highway to get it to misfire and set the CEL (the code tells you which cylinder is behaving badly). if you get a P0300, its a generic code but if there's a digit at the end say a P0303, you know its cylinder 3 and you can then swap the coil with an adjacent cylinder to see if the misfire moved there to confirm the coil is bad. With the coils off, its a good time to replace the plugs too.