2007 S80, suddenly won't start?
 

Hello all. I have an S80, V6/3.2L with a recently replaced PCV oil trap. Since replacing, it idles rough, around 600 rpm. When standing outside the car it almost sounds like the exhaust is clogged.
I went outside this afternoon, and suddenly it won't start. I can hear a clunk when pushing the start button, but nothing else. The only 2 messages that appeared on the dash were:
1: STOP - ignition is on
2: DTSC is temporarily disabled
Also, every single light on the dash is on. One time I did notice the CEL was flashing.
That's really all I have. *sigh* any pointers or ideas?

Let's start with the simple stuff. Make sure that the battery is fully charged and that the cables are on tight. I suspect that all of this was undone when the PCV system was serviced.

* BATTERY TERMINALS

If you look at a battery post from the side, you will see that it is slightly cone-shaped. It is not a cylinder-shaped post. As such, you need to loosen the terminal clamping bolts a bit and take a small screwdriver and spread the posts apart a bit and wiggle them onto the post before tightening. I've seen cars come through where the terminal was tight, but you could lift it right off the battery post. This problem is caused by the person tightening the terminal but not securing it far enough down the post. The result - warning lights, fried alternator, power loss, electrical fire, etc.

https://volvoforums.com/forum/general-volvo-chat-5/tips-volvo-owners-97149/

There is no need to touch the battery when replacing the PCV breather box, but I agree you need to start by making sure the battery is good.

Do you have any power in the vehicle, dash lights?