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http://www.volvo-forums.com/t25052-need-help-with-these-codes-p0810-p1618.htm

http://www.brickboard.com/AWD/volvo/1064512/V70/trouble_codes_p0810_p1618.html
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...i may as well continue with the ridiculour replies...
Sounds to me like you got a banana skin wrapped around your drive shaft and too much ice cream on your disc brakes, causing an imbalance at...

Ball joint or wishbone bushes

sounds like ball joint play

i had this once a long time ago,on a ford orion if i remember,turned out worn inner cv..changed the shaft,all luvely after........

I am prety sure you can obtain a small device to fool the system, go on e-bay. Check out CANBUS.

you need a HID system with CANBUS, volvos sense current draw for the bulb failure system, i have fitted HIDs to an 850 and to my current V70 with no probs.

I think this can be a common problem as the HIDs use a ballast to start the lamp. It would give an inconsistent impedance which would be seen as a fault by the car. The more expensive HID kits, I...

Now, back to the car!
coat the inside of the wishbone hole with good ol' copperslip
http://i1100.photobucket.com/albums/g413/martinrpeachey/polybushandshocks/DSCF6966.jpg
Using your socket...