Hi, I own a mechanic shop and this car came to me about two weeks ago and I haven't been able to fix the problem. The following is everything that has happened so far.

The customer came to me with an ETS light on, and heavy noise when driving. During my test drive I found that that the heavy noise was caused by bad motor mounts, I knocked those out of the way and it fixed the noise problem.

I cleaned the ETS (Throttle Body), but the light was still there and something new came up. During my initial test drive, I drove really slow due to the noise. After fixing that I took another test drive. When I press the accelerator the vehicle acts like it goes to neutral and pushing the accelerator farther will just shoot the RPM up. I had to let go of the accelerator for it to catch and I could drive again. This happened at 2500 RPM. It kept doing the same thing over and over at the same RPM.

I was afraid it was the transmission so I checked the fluids and it was okay. I want to flush it with a filter change but I have to actually drop the transmission for that.

A check engine light came on and the there was a transmission code (only came up cause I kept pushing hard on the RPM to see what would happen) and a Mass Air Flow. I changed the mass air flow but nothing. I then changed the actual throttle body next and ETS light went away but the problem persisted. I checked for leaks everywhere and did everything I knew but couldn't find anything.

I finally gave up and took it to a Volvo dealer. They charged $240 to do a software update on the ETS (necessary when changing the ETS) and $145 for a diagnostic. The diagnostic showed that the Turbo sensor aka MAP sensor (not Mass Air Flow) needed to be changed. I checked the check engine light code again after the update and all the other codes were gone except the turbo sensor. Feeling dumb, I changed the turbo sensor BUT AFTER EVERYTHING THE PROBLEM DID NOT FIX.

I figured the sensor was defective and exchanged for a new one but still nothing. I've cleaned the plug, checked for leaks but nothing. I am completely clueless as to what to do now. Anyone know something???

A tune-up was recently done so that's not it either. HELP!!!!

 

If the MAP sensor is throwing the code, perhaps the pressure in the manifold is off somehow? Do you have a spare boost gauge you could hook up and see what the turbo is doing? Maybe it needs a new wastegate spring/seal. I've also seen a video on youtube of a vacuum hose collapsing during highway pulls and it throws the pressure way off. Maybe replace some lines even though they aren't leaking. (BTW, not a mechanic, just trying to help make educated guesses)

Here's that video I mentioned:


I know this video is for an 850, but the first gen C70s have almost identical engine bays.

 

Thanks but I found out what happened. One of my techs (None will say who, I'm getting ready to fire them all!) topped off the fluid from the dreaded 27 mm bolt on top of the transmission. Once that bolt is removed, the B4 band is disengaged, and there is no 3rd gear. All the symptoms make sense now. Check Engine is now gone, turbo is good. I need to know how to reconnect the B4 band back into place. It is not a common practice, but it is definitely possible. Does anyone know how?

 

According to Volvo, the trans needs to be disassembled to do so. I have never had one out to try to reconnect it so I'm not sure how to go about trying it in the car.

 

I have successfully fixed it when somone removes the third gear anchor bolt. Here is a thread : Just bought a 2001 c70 that seemed to flare in 3rd - Volvo Owners Club Forum and another http://www.volvoxc.com/forums/showth...ill-not-engage