OK, I have to admit I'm NOT KLAUS (nor CHRIS) ... but I believe there is "some" good advice between the TWO of them ... 'Just had my '07 V70 wagon (250K miles) at the dealer last week for the same reason ... a slight clunk when accelerating ... along with a recently lit (HINT!) check-engine light and ABS warning lights ON. Of course, I thought O2-sensor, ABS module replacement, and engine mounts (the three typical suspects from similar bricks I owned dating back to '97). But, alas after a $240 diagnostic charge (and a long laundry list of 'recommended' items per KLAUS's post), I asked to talk to the TECH that worked on the car: he said it looked like I had some "non-dealer brake and bearing work" done recently (he was correct!).... and DRUMROLL ... the non-dealer mechanic apparently did not tighten the BOLT through the front-left axle. The axle had enough slop to confuse the ABS system, and throw a "P0500" code, "requiring" (per Volvo diagnostics) a new steering angle sensor, front axle replacement, bearing replacement, hub kit, and labor ... all adding up to $2.4K. When asked whether it was dangerous to drive the car, the Volvo TECH said he tightened the bolt, and all errors disappeared ... and ANOTHER drumroll ... no more CLUNKING upon acceleration. I'm going back to my long-time non-Volvo mechanic to double-check on that front left axle, tell me if it is possible that his tech forgot to tighten that bolt, and give me his recommendation on whether any further work/parts are needed.

'Hope this helps.

Bernie