Surging/Oscillation/Pulsing, etc.

**mattcp67** · 09-26-2006, 12:25 AM

OK, so I know this has been discussed here before, but I thought I would throw a new variable into the mix and see if anyone has had the exact trouble I have had. I have an 02 XC70 with ~70k. I have owned it for a year and my trouble started a few months ago. All service has been performed; I run 92 octane.

Trouble:
When maintaining any constant speed on a flat surface or slight incline (loading engine, not coasting), where RPM's fall between 1400 and 1800 I get an oscillation in RPM's that's seen on the tach as 100 to 300 rpms and felt as a surge. It does not happen at freeway speeds or RPM's below 1400 or above 2000; it runs smooth and strong.

Now for the twist.

If I flip the tranny to geartronic while the oscillation is happening - it goes away - when I flip it back to automatic - it returns. The trouble simply does not exist when using geartronic at any speed/RPM combination. I have duplicated this for the dealer mechanic on a 30 minute test drive and he is perplexed but doesn't think it is the transmission.

Solutions I have seen on this forum, that didn't mention the geartronic twist, were:

VADIS ECM/TCM updates
Turbo Solenoid replacement
ETM replacement (perhaps limited to 01's and prior??)
Throttle body cleaning
Tranny Solenoid replacement
Intercooler hose trouble
Turbo Boost Valve control
Tranny replacement

In addition, I have been told that there are no open VADIS campaigns against my VIN. My normal independent mechanic says he has no idea and referred me to the dealership after puzzling over it for a day (he hasn't worked on to many 02's yet). The dealership wants the car for the whole day to try and troubleshoot. I have a third party extended warranty to 100K, but they have to diagnose and call for approval before replacing anything - luckily I bought the top-o'-the-line warranty and it covers tranny replacement.

All input is greatly appreciated. Please feel free to comment on the geartronic solution - I don't mind using geartronic all the time but it gets tedious in heavy traffic.

**kimmoyle** · 09-27-2006, 01:29 AM

You have done a better job than I in describing the problem of surging. I just placed a post about this issue. I am assuming that you have not had any of the suggested remedies conducted? We had Volvo's extended warranty on our 01 XC. From reading what others have wrote it does not appear the ETM is upgraded in the later models (I'm sure someone can check this out by the part numbers). Maybe the later models have different software programming that prevents the ETM from failing (some have suggested a carbon issue).

Anyway, we had the software upgrade, the throttle body cleaning and finally the ETM replaced. If it were not for the fact, that we were persistant, I don't think Volvo or the dealership would have replaced the ETM (which has made the engine more responsive and powerful).

The new ETMs in these Volvos from 1998 on are Bosch and very much dependent on software that run it. I suspect that the transmission experiment that you have done effects some variable which then is programmed to have an effect on the ETM and how much air/fuel gets to the motor. Sorry, I can't be of more help and good luck to you.

**mattcp67** · 10-03-2006, 05:11 PM

this is a bump

**littlewaywelt** · 10-04-2006, 02:01 PM

Originally Posted by mattcp67

OK, so I know this has been discussed here before, but I thought I would throw a new variable into the mix and see if anyone has had the exact trouble I have had. I have an 02 XC70 with ~70k. I have owned it for a year and my trouble started a few months ago. All service has been performed; I run 92 octane.

Trouble:
When maintaining any constant speed on a flat surface or slight incline (loading engine, not coasting), where RPM's fall between 1400 and 1800 I get an oscillation in RPM's that's seen on the tach as 100 to 300 rpms and felt as a surge. It does not happen at freeway speeds or RPM's below 1400 or above 2000; it runs smooth and strong.

Now for the twist.

If I flip the tranny to geartronic while the oscillation is happening - it goes away - when I flip it back to automatic - it returns. The trouble simply does not exist when using geartronic at any speed/RPM combination. I have duplicated this for the dealer mechanic on a 30 minute test drive and he is perplexed but doesn't think it is the transmission.

Solutions I have seen on this forum, that didn't mention the geartronic twist, were:

VADIS ECM/TCM updates
Turbo Solenoid replacement
ETM replacement (perhaps limited to 01's and prior??)
Throttle body cleaning
Tranny Solenoid replacement
Intercooler hose trouble
Turbo Boost Valve control
Tranny replacement

In addition, I have been told that there are no open VADIS campaigns against my VIN. My normal independent mechanic says he has no idea and referred me to the dealership after puzzling over it for a day (he hasn't worked on to many 02's yet). The dealership wants the car for the whole day to try and troubleshoot. I have a third party extended warranty to 100K, but they have to diagnose and call for approval before replacing anything - luckily I bought the top-o'-the-line warranty and it covers tranny replacement.

All input is greatly appreciated. Please feel free to comment on the geartronic solution - I don't mind using geartronic all the time but it gets tedious in heavy traffic.

That's exactly how our 01 xc behaved prior to etm failure, although ours was mostly at highway speeds.
Mileage was about 65k at the point it failed and it started acting up probably at 50k.

**markwemple** · 10-04-2006, 02:41 PM

Originally Posted by kimmoyle

You have done a better job than I in describing the problem of surging. I just placed a post about this issue. I am assuming that you have not had any of the suggested remedies conducted? We had Volvo's extended warranty on our 01 XC. From reading what others have wrote it does not appear the ETM is upgraded in the later models (I'm sure someone can check this out by the part numbers). Maybe the later models have different software programming that prevents the ETM from failing (some have suggested a carbon issue).

Anyway, we had the software upgrade, the throttle body cleaning and finally the ETM replaced. If it were not for the fact, that we were persistant, I don't think Volvo or the dealership would have replaced the ETM (which has made the engine more responsive and powerful).

The new ETMs in these Volvos from 1998 on are Bosch and very much dependent on software that run it. I suspect that the transmission experiment that you have done effects some variable which then is programmed to have an effect on the ETM and how much air/fuel gets to the motor. Sorry, I can't be of more help and good luck to you.

Please be more specific about these upgrades as I would like to check into them for my 2001. Thanks!!

**rkestner** · 10-16-2008, 02:37 PM

Same problem here as originally described by Matt, but with the following diagnostics additions. IT DOESN'T HAPPEN IN CRUISE CONTROL. IT DOESN'T HAPPEN IN SET GEAR.

After 2 days at the dealers, we have determined that the transmission is jumping from 4th to 5th and back under the original conditions described (25-35 mph, level or slightly uphill, surge in rpm from around 1500 to 2000).

From a systems point of view, it has to be something on the throttle side, that is, unique to the throttle side, since it doesn't occur in geartronic or cruise contol?

BTW-Dealer recommended new transmission but would NOT guarantee that it would fix the problem. VNA responded to a letter by stating that dealers are the final authority on technical issues for customers.

Anybody got any other ideas?

Thanks

OSD Rich

**KB1** · 10-17-2008, 08:44 AM

I have the exact symtoms as explained by matcp67. I bought the car few months ago and being frustrated with the vibration. I took the car to a local shop that specialize in Volvo cars but the computer didn't read anything. This vibration goes away if I push the gas pedal or take my foot off the pedal. I have been using the Tiptronic on local street to avoid the NVH. I did flush the trans three times (two by shops and once myself) but seems to have no big effect. Just called the local dealer and the service manager said, it sounds like trans solenoids.

I see this problem was reported in 2006, but if any body have any updates, please report.

**PGI007** · 10-17-2008, 09:28 AM

Are you getting vibration AND the RPM surge? With my 05 I have always noticed a "roughness" as it hits around 1500 rpm going about 50-60 km/h, but no rpm surge. I took this to be normal, and my indie mechanic says the car runs fine. If there is something amiss I would also like to know as the car is still under warranty.

**rkestner** · 07-28-2009, 07:51 PM

Great descriptions and analysis. Over the past 2 years have been to dealers (plural) and even had the regional service rep come down to NM from CO to take a look. In the end, it is the torque converter locking and unlocking, but we still do not know WHY. From a purely logic point of view, it has to be something NOT common to accelerator and cruise control since it does not happen in cruise control but does when using the accelerator. Volvo rep and dealers say replace the transmission, BUT they will not guarantee that this will resolve the problem. Sooooo......we have decided to keep driving until the transmission goes out. In the meantime, we use cruise control, use the shifter to lock in 4 or 5 gear or otherwise try to compensate. The Volvo regional service rep experience was earlier this year at around 120K miles. We have just turned 150K and still going strong.