I have a question regarding the ETM on my 2001 T6. The ETM was cleaned about 30000 kms ago and I have the software upgrade, as well as a new air filter and new turbo control valve. My idle is mint, no issues and no stalling. What I do have is surging under full throttle and very slight surging while highway crusing. When I am on the highway, you can feel the throttle changing constantly in minute amounts and it is worse when it is wet or really humid. I don't have any check engine light or emission service lights ever.

Could this be the beginning of a bad ETM? How bad does it have to be before the dealer will fix? I just want to make sure I am armed with information before I go in and have them diagnose it and charge me for stuff I don't need.

 

It might be the ETM.
Usually if it has been clean and updated if a code comes bad for it they will replace it.
Is the A/C on when this happens?

 

It happens either with or without the A/C. The highway surging is more noticeable when the A/C is on as the compressor is engaging/disengaging. It is the same also with the cruise control or the pedal. I have also had 3 random instances where I pushed the gas pedal from a stop and the car waited a split second before it began to accelerate, almost like the ETM didn't sync to the gas pedal movement. Also, the first maybe 1/5th of the pedal travel has nice easy acceleration, then I hit a spot where it really takes off, not really linear.

I have never owned a car with "drive by wire" so I am not sure what to expect, perhaps this is normal??

 

Sounds liek the ETM is on its way out.

 

Thanks Tech, you have confirmed my suspicions. Now I have to convince the dealer. Do you know if they will replace it based on drivability concerns or does it have to throw a code first?

 

Usually it has to throw a code but if it runs/drives really bad they might.

 

I will have to speak to them about it. I read somewhere that the software update makes it more resistant to throw codes and delays them having to replace the ETM, any truth to that?

 

Yes that is true.

 

I think there is something going on with your ETM and you should try to get this fixed first. However air mass meters can some times also causesimilar problems. On full-accel that could be the turbo control valve but you said you had this replaced. Check to make sure there isn'ta small crack in one of your air intake hoses espaciallyafter the turbo.
The hesistantion on takeoff may be a symptom of a feature know as neutral control.Do you feel a little 'jerk' when this happens or is it simply no response at all?
What does your tach do when you "feel" the throttle change at highway speeds?
I will be posting a seperate thread on ETm issues

 

The MAF has been replaced about 40000 kms ago according to the service records. The full throttle surging is intermittant, so am not sure if it is a intake leak. The hesitation off the start only happened a few times. One diagnostic thing I tried was putting it in manual mode in 1st gear. I put my foot on the gas and it would hesitate slightly and then take off like a shot, very jerky.

On the highway while surging the tach stays the same. It feels like the a/c compressor turning on and off every few seconds even though the a/c isn't on.

 

OK, some more info. The weather has gotten cooler here and the full throttle surging has disappeared, but the constant throttle surging is still present. It gets worse as it get more humid and is almost nonexistant in cold dry air. I am starting to think the two problems are not related. I think the full throttle could be detonation and the computer is backing off the turbo/timing to make it stop when it is warm out. The previous owner was an old guy that probably drove it really easy and it could have some carbon buidup in the combustion chamber. The constant cruise surging is either the ETM or MAF. I am going to swing into Volvo today and see if I can get one of the mechanics to go out with me and check it out.

 

if yout mileage are within the ETM exclusive extended warranty you are eligible for a new etm if at dealer they traced to a faulty throttle unit. they will run a ETM test via vida and it will shows the conditions of yout potentiometers inside the throttle. if your throttle is bad also check the pcv if it is clog or not.

 

Where are you? The 10-year 200,000 mile warranty is only for North America. Volvo says, "10-years is 10-years" and has refused a warranty replacement at 10-years and 6-weeks even though the symptoms were reported within the 10-years.

I am testing a non-contacting ETM that will be on the market very soon.

I am looking for Volvo Forums beyond North America as well as automobile editors for magazines, newspapers, radio and TV. If you know of any send an E-mail to NONCONTACT-ETM@COMCAST.NET.

Don Willson