CEL - P0234 -Overboost - possible causes?

anelson52 · Post by **anelson52** » 19 Jan 2009, 19:18

I have a 2000 S80 T6 with 140k miles. About a month ago I had the CEL come on, registered as a P0234 Turbo Overboost. That light cleared when I had to change the battery out about a week later (faulty cell). I ordered and installed a new boost pressure controller and changed all of the vacuum lines to it. Everything seemed fine until today when the CEL came on again. It came on as I was excelerating from about 35 mph to 65 mph, after slowing to move past an accident on the interstate.

My reader shows another Turbo Overboost condition. Any thoughts on what else might be the issue? I've had the ETM software updated (mid '07), changed plugs about 2k miles ago, and I change oil about every 3,500 to 4k miles with full synthetic.

Any help would be appreciated! Thanks

Post by **MadeInJapan** » 19 Jan 2009, 19:40

Could be that the wastegate is overly tightened. If you're not familiar with this, get an independent Volvo shop to check it out.