2001 S60 - Car surges and chugs at highway speed and braking

ldjohn · Post by **ldjohn** » 02 Sep 2010, 15:26

I have a 2001 S60 (no Turbo) with 140k miles on it. When I am driving at a constant speed it wants to surge (pick up speed) and then fall back to the speed I was driving (maybe 3 mph surge). If I try to maintain speeds around 30-40 MPH it will start to lurch or chug back and forth and when braking while the engine speed is still coming down it can be hard to stop. It still wants to speed forward. If I consciously let off the gas and do not brake till engine had idled down it does not do it. It seems fine during acceleration, problem appears when trying to maintain a constant speed or slowing down.

Thanks

jda2000 · Post by **jda2000** » 03 Sep 2010, 07:25

does it have the original ETM? has the throttle body ever been cleaned?

ldjohn · Post by **ldjohn** » 07 Sep 2010, 22:40

I belive the ETM is original. It had a problem a couple years ago where the car went into Limp Home mode and there was a recall. It required updating the software/program for the ETM. I am pretty sure it wasn't replaced.

How do you clean the ETM?

Sorry for the slow reply, out of town.

ldjohn · Post by **ldjohn** » 07 Sep 2010, 22:41

Sorry, I meant how do you clean the throttle body.

jda2000 · Post by **jda2000** » 08 Sep 2010, 07:54

remove the ETM from the intake and clean the throttle body/plate with carb cleaner.

The cleaning might help, but most likely the ETM has failed/is failing. The ETM has a 10 year warranty, so yours is coming to an end very soon. A trip to the dealer might confirm it and you might get a free replacement ETM.

ldjohn · Post by **ldjohn** » 10 Sep 2010, 16:03

I called the local Volvo dealer and talked to their service department. They did confirm that there is a 10 yr. warranty on the ETM but only if it fails. It has to fail what they call a "Sweep Test". Not sure exactly what that is. I would have to pay $130.00 to hook it up to read the diagnostic codes and if it pointed to the ETM they would run the sweep test. If it fails they will replace it for free. If not, I will have to decide what I would do next. Minimally it will be $130.00. He said the surging/chugging could be caused by a number of things.

One thing that I forgot to mention is that a few times when I first jumped in and started the car and waited for a few seconds the engine would rev up and it would be difficult to get back down to idle speed. It would stay at about 2400 RPM I would rev it up a few times and would eventually come down or I would put it in drive and it would force it down and then it would be fine. Now I am usually in such a hurry that once I start it I don't have time to wait for it to rev up and am putting it in gear right away. This will change soon as winter is coming. Does this sound like an ETM problem?

evans_sa · Post by **evans_sa** » 16 Sep 2010, 12:34

by no means am i a mechanic nor have the slightest idea regarding car issues but i did and currently do have a similar issue and thought i could share my experience with you with the hopes it'll help.

the first time i had problems with my RPM gauge fluctuating was about a year ago. i could have sworn i needed an new ETM (i too have a 2001 non-turbo S60) but after the dealership inspected my car i was denied the recall ETM and instead was informed that my PCV/vent box was leaking oil, the attached hoses needed replacement along with my CAM seals. apparently all important as the leaking oil can cause your timing belt to slip off! since i couldn't afford the repair to be done at the dealership (~$1,000-$1,200) i had a friend of a friend who is a toyota mechanic make the changes. however, my car has recently been acting up again (just as you described it especially around idle speeds of 30-40 mph). i just happened to be at the Goodyear shop for a temperature gauge replacement (check engine light on) and the mechanic informed me that my PVC box is leaking oil and my CAM seals need to be replaced?! so either i got scammed on the first repair job OR something else is causing me to go through PVC boxes like hotcakes!! still trying to figure it all out but will let you know.

ldjohn · Post by **ldjohn** » 29 Sep 2010, 01:19

About 3 years ago I too had to replace the same compnents along with the master brake cylinder but it had different symptoms. If I remember correctly it would not idle without stalling. Still could be related though. Thanks for the post. Let me know what you find out.