Long time lurker (re the ol' 1992 740 with 245k!)...new member...with "new" 2000 V70XC with 156K.

First, thanks (from me and my mechanic!) to everybody on Volvo Forum that guided me through ETM diagnostic and remanufacture (via Xemodex). It worked!

Now, on to my next issue:

I'm not certain these things are related, but I'm beginning to suspect they are. The noticeable symptom is an unsavory ca-CHUNK that I can hear and FEEL when slowing. It hits (and I do mean HITS) around 10 MPH - feels like it's coming from the rear end...maybe. Feels to me like a rough downshift? Also, Check Engine light is on, and there's a blinking arrow on the dash that the manual says is used to indicated it's in "W" (winter/wet) driving mode. I just had the Check Engine Light code checked, and though I don't know the exact code number, my mechanic referenced what he described as the "Transmission Speed Sensor" (and I see is called the Vehicle Speed Sensor (VSS) by Volvo) giving no signal. He pointed out the part to me - a little white connection with a wire tailing into, I think, the computer box - pretty accessible under the hood, on the drivers side.

He reset my Check Engine light (and the blinking arrow went off as well, I noticed), but it was back on before the end of the block. The instant it came back on, so did the blinking arrow.

I have done a bit of reading on other threads, and I see the ABS module is linked in with this system, but I do not have ABS light on dash - only Check Engine and his partner, the blinking "W" arrow indicator. Also, no ABS related codes.

I am going back to my mechanic on the way home tonight and I'll get the exact code...so more on this tomorrow...but my questions for now are:

Would this VSS sensor failure cause what appears to me to be a rough downshift upon stopping?

My mechanic is always happy to guide me in repairing things when I'm able...he has PLENTY of business...and it looks easy to swap this VSS...but I want to avoid a misdiagnosis. Is there any way to confirm this is the problem, other than switching the part (which I see costs about $110 or so)? Something I can check or see in the part that will confirm?

 

I got the Check Engine codes from my mechanic (Denis) yesterday - don't know if this helps, but they are:

P1618 - Lead between transmission and computer

P0722 - Speed Sensor Circuit - no signal

Seems to point to the VSS to me (and to Denis)...