Transmission Issue?

Hi all,

I've owned my 2002 golf tdi for about 4 months now and absolutely love it.

However, recently it has started to give me an issue. It accelerates as quickly as it did when I bought it up until about 45 mph. Between 45-55 mph it really struggles to accelerate, I think it might be the vehicle not properly shifting into 3rd? gear. It is an automatic.
After this occurs, and if I come to a stop after this, it struggles to accelerate half as quickly as normal between 0 - 55 mph.

I've noted that this problem can be solved if I turn the vehicle off for a brief moment and then on again, it seems to go back to normal after I do this.

I honestly know nothing about cars, and am sure I will learn a lot as I continue to post around here.

If I have left out any vital information, please let me know.

Thanks a lot everyone.

What you're describing reads like "limp mode". The place to start is the vacuum lines to the N75 valve that works the turbo. Could be the N75, a leaky/cracked vacuum line or a sticky actuator. Do a search.

RT1 is probably right.

I would like to clarify that transmission limp mode is not the same as Limp mode due to a overboost code.

YOu probably have a overboost code.

Overboost or underboost causing limp mode to protect the turbo. Get it scanned for codes and do some logging with VCDS. Lots of info here on this issue.

Alright fellas,

So if you couldn't already tell I know nothing about these things, this will prove it:

So what I get from what you're telling me is that I either "overboost(ed)" -and I interpret this as accelerating too hard- and the computer told the engine to cool it down.

Does this sound like a serious issue with the given information?
How much could this cost me?
I will take it to a "trusted tdi mechanic" there is one 15-20 miles from here, in Ann Arbor.

Thanks a bunch, you guys are awfully helpful.

JMurphy said:

Hi all,

I've owned my 2002 golf tdi for about 4 months now and absolutely love it.

However, recently it has started to give me an issue. It accelerates as quickly as it did when I bought it up until about 45 mph. Between 45-55 mph it really struggles to accelerate, I think it might be the vehicle not properly shifting into 3rd? gear. It is an automatic.
After this occurs, and if I come to a stop after this, it struggles to accelerate half as quickly as normal between 0 - 55 mph.

I've noted that this problem can be solved if I turn the vehicle off for a brief moment and then on again, it seems to go back to normal after I do this.

I honestly know nothing about cars, and am sure I will learn a lot as I continue to post around here.

If I have left out any vital information, please let me know.

Thanks a lot everyone.

Click to expand...

One question, When was the last time the trans had a filter and fluid change?

If was over boost you would have a check engine light.

Is the engine revving higher than normal to go the same speeds as before ?

If so.. you may be having mechanical malfunction of the torque converter. Sometimes misdiagnosed as a 'slipping torque converter'. When you say it struggles to accelerate half as quickly as normally, do you mean the engine is struggling to get to the same revs, or the car is revving high than normal but the car is barely moving in comparison ?

I had this situation similar to what you are describing and I too could make it go away by turning the car off and then on again (but not every time).

If this is the fault expect it to continue and spread through all the gears.

My solution was to swap out for a manual tranny. Makes all the difference in the world. And don't be intimidated my sister could drive a diesel manual transmission (and thats saying something).

If explained properly they are nearly impossible to stall without ever touching the gas pedal.

Your description sounds like limp mode induced from the turbo's variable vanes not moving properly. It is a relatively easy repair. I had the same issue with my 2002 Jetta auto I bought recently. My problem was actually underboost, the previous owner had the dealer clean the intake and they left 2 bolts out of the egr to intake connection, which would not allow the turbo to build boost. My car would accelerate slowly and did not throw a check engine light. It would also rev much higher before shifting.

If your variable vanes are sticking, your engine's computer will put the car into safe mode, aka limp mode to protect the engine. The fact that you can turn the car off and back on and it runs normally for a while comfirms you are going into limp mode. I would suspect your VNT actuator or VNT mechanism. You can search this forum for chemical turbo cleaning, which some have used succesfully. Worst case you will need to remove the turbo to clean it.

You will definitely need to have a trusted mechanic from this site evaluate your car to see what the problem really is. I am betting you can get this repaired pretty cheap.

Diesel Nut 247 said:

One question, When was the last time the trans had a filter and fluid change?

If was over boost you would have a check engine light.

Click to expand...

Lots of folks drive with a glow plug code anyway, so they never know when their light comes on.

A bad MAF doesn't turn on the check engine light very often.

I haven't replaced the tranny's fluid or filter since I've owned the car, and the previous owner doesn't really have any records about it.

mstar, the car is struggling to get to the same revs. when this problem occurs, however the car does get awfully loud, I suppose I never really checked the revs, now that I think about it.
Also, the check engine light has been on for months, it was diagnosed as something to do with the glow plug wiring harness, but the car has started fine and I haven't done anything about it. So, i am unsure if the problem I am experiencing has triggered another cel code.

I plan to take it to these fellas in Ann Arbor. I will keep all of you posted.

Thanks a lot everyone.

My car would struggle to maintain speed (while on cruise control) going up hills. The revs would start climbing while the speed slowly dropped.

Alot of us have that CEL from the stupid glow plug harness. Thats no big deal, although hiding in the VCDS was the torque converter malfunction code I was also getting. As I understand it this code is much like a limp mode for the transmission. Which would explain why it would clear itself and not show up on VCDS unless I was experiencing the problem at that time.

If was over boost you would have a check engine light.

Click to expand...

On the few occasions I encountered limp mode from over boost there was no CEL but it does throw an error code which you can read with VCDS.

Quick update: I checked the revs while it occured today, and it only struggles to get to the same rpms. The engine struggles to get to the same revs it did.

Hope this might clear some confusion up.

And, what exactly is overboost? I searched the faq and I couldn't find the answer.

JMurphy said:

So what I get from what you're telling me is that I either "overboost(ed)" -and I interpret this as accelerating too hard- and the computer told the engine to cool it down.

Click to expand...

What overboost means is that due to some malfunction the MAP sensor saw more boost than the computer will allow. When this happens it triggers a code, turns on the check engine light (maybe not according to Lee Taylor) and the computer stops allowing the turbo to make boost. This is commonly refered to as "limp-mode" (not the same as transmission limp-mode, sorry I'm a trans guy).

Diesel Nut 247 said:

If was over boost you would have a check engine light.

Click to expand...

CoolAirVw said:

Lots of folks drive with a glow plug code anyway, so they never know when their light comes on.

Click to expand...

JMurphy said:

Also, the check engine light has been on for months, it was diagnosed as something to do with the glow plug wiring harness, but the car has started fine and I haven't done anything about it. So, i am unsure if the problem I am experiencing has triggered another cel code.

Click to expand...

Wow! I nailed that one!