Hi guys, I'm having an odd issue with my S70, as I'm still trying to better understand these cars, I figure this is the best place to ask.

I'll be driving along on the freeway with my cruise set and it will almost feel like the car drops into neutral and the cruise cuts out. There was one instance where my speedo dropped about 10mph and then jumped right back up where it was supposed to be.

The car shifts and accelerates just fine, and the trans doesn't slip. I also don't have a flashing arrow light on the dash. I'm hoping this might just be a sensor issue or something. Has anybody else experienced something like this? I did take a sample of the fluid (changed about 10k miles ago) and it was still fairly clean, and it was not metallic. TIA.

 

does this only happen when its on cruise control or will get get a drop out from time to time with your foot on the pedal?

 

I've only really noticed it in cruise, but it feels like the car goes into neutral (not slipping, just driving along and the RPM's drop and saw the speedo drop once then come right back) that is what makes me think its a sensor issue

 

Agree with MT6127. See if it does it only with cruise or also with your foot on the pedal.

 

I drove it about 40 miles one way to class last night with the cruise set on the way there, and not on the way back... it didn't act up. This seems to be a very intermittent issue.

 

That's not neutral. That is cruise shedding.

When a car drops into neutral, with the cruise on, the rpms go up a lot, like to the redline.

This is a speedometer problem.

 

That makes sense, so a problem with the speedometer itself of the Vehicle Speed Sensor?

 

Who knows? The cruise works by computers talking to each other across a network. i don't know if the speedometer is involved in that conversation or not. One thing is for sure, the problem, whatever it is, is taking the speedometer offline. That we know.

 

Is your ABS and/or TRACs light on by chance? If so, I'd get you ABS module fixed and that may just fix this issue too.

 

The lights are on, the codes are for a Right Rear wheel speed sensor, I did determine that the sensor itself has an open circuit.

But being that the vehicle speed sensor is on the transmission, I wouldn't think this would matter, would it?

 

Fix your ABS module and reasonably sure it will fix your CC issue too.

https://www.midwest-abs.com/Troubleshooting.php

BTW how did you determine your RR wheel speed sensor is faulty?