Hi Volvo forum,

I have a Volvo V70 2.4 N/A 2001

Engine code: B5244S

The car symptoms is: Vibrations at idle, though pretty steady revs. While slowing down towards a red light the revs jumps up to 1200-1300 rpm when gearing down (automatic transmission) when fully stopped the rpm "really slowly" falls to idle 700-800 rpm with vibrations again.

Has anyone experienced this?


Things I've hanged/done:


Original spark plugs
PVC oil trap + hoses
Throttle body unmounted and cleaned
Vacuum hoses from inlet manifold changed/checked

Flap in airfilter box is set to fully open towards cold air and closed for hot from exhaust manifold.
All engine mounts has been changed (also transmission mount)

 

The ETM being worn and needing a rebuild came to mind. The old MM ETMs have a mylar strip which wears out and effects operation.

Then your description of the odd revving upon slowing down at a red light made me wonder if the transmission was disengaging properly.
I'm no transmission expert but I suggest you check to see if the fluid is clean by doing a drain & fill.
Wiping a dipstick on a rag does not tell the story dumping 3.5 to 4 quarts of fluid does. We all know color isn't too scientific a test but we know jet black fluid or brown fluid (I've seen it with lumpy chunks in it) or anything other than clear red spells trouble.

Use Toyota Type IV (T-IV) fluid or MaxLife Dex/Merc LV if you don't want to spring for the Volvo stuff. Do not use plain old Dex/Merc.

Also take your VIN to a Volvo dealer and see if your transmission has had its updates. A $60 update years ago improved my 2002's operation.

 

Thank you very much for your reply.

I didn’t mentioned that I’ve changed the valve body in the transmission along with a complete flush and filter about 15.000 km ago combined with a software update at Volvo. The transmission has been flawless since.

I’ve never done anything to the ETM besides cleaning it. Maybe I should change the throttle position sensor in the throttle body.

If I remember correctly the revving upon slowing down started after changing PVC oil trap and setting the flap in the air filter box to cold air. Can it be related to the the flap?

 

I doubt setting the intake air temperature control flap (to one fixed position, why?) would have the effect you're experiencing.

Why'd you do that? IAT (Incoming Air Temperature) is important enough that there's a sensor (pychnometer, no?) for it.

How many miles on your car? Has the ETM ever been changed? I've read that the XeMODeX rebuild uses newer, better technology.
If a Volvo dealer replaces your MM ETM you get a duplicate of the original, weak design.

Of course I'm not saying your ETM is bad. I don't know.

 

I agree with George regarding checking out the ETM. google around for "Volvo ETM contact repair kit" - IPD USA and ardideas.com are a few sites I'd visit to see if they carry. There are also vids on Youtube

 

Thanks again for the replies.

I did it because the flap was stuck in the hot air position due to a faulty thermostat in the bottom of the air filter box. See for example This thermostat is not possible to buy without buying the air filter box at Volvo :-(.
The car has 475.000 km on it. (about 300.000 miles). I think the ETM has been changed before I owned the car because it has the ETM with the yellow label.

I think I will buy a throttle position sensor https://www.ecu-auto.com/home/42-con...0-v70-c70.html for the ETM and see if it helps.