Hi all,
I have a 2001 S40 1.9T with 91000km on it. I bought the car used about a year ago. It had 79000km when I got it. I had all the recalls done when I got the car. Over the course of the year, I had the check engine light come on 3 times for the same code in the first 11 months I had the car. After the 3rd time, my Volvo garage suggested to replace the Camshaft Reset Valve Sensor (used for the variable valve timing). They part was not expensive, so I said to go ahead. Since then (this had been 1 month), the light has come on 4 times!!!! They looked into the problem some more and found out that the problem could be caused by sludge. So, they did a flush and put in synthetic old (they did find quite a bit of sludge too). For the heck of it, I called the dealer to lookup the previous owner's record and they told me that he only changed his oil at 13000km intervals with them!!!! This is too much, so I am hoping that he changed the oil at other local garages (but this would make sense if sludge is the problem). I had the light reset last week, and it has come on again, so I just wanted to see if any of you have any ideas? At this point, I plan on driving it for a few months with the light on, and just tell them to do another flush treatment. Can a buy some sludge cleaner to mix with the oil? Let me know if you have any ideas.

Thanks, in advance