Problem with my wife's VW Passat

[KahrMan]

We have a '03 Passat with 50k miles on it. It has the 1.8l turbo 4 cylinder engine. This is an intermittent problem. She will be driving along and the rpms jump up to around 7k and the speed drops to about 20 and will not go any faster. While this is happening the display for PRD432 will either all highlight or none will be highlighted. Sometimes the D even disappears. When this happens she will shift down to 4 and the car will drive like you would expect it to in 4th gear. She can drive about 40 without the rpms getting to high. She will drive for a couple of minutes in 4th and then switch it back to Drive and everything is back to normal.

This has happened twice now. Once when my son was driving and again today when she was driving. I test drove it between these two events and it drove fine for me.

Anybody have a suggestion as to what is going on? Also anybody have any suggestions for a reasonable VW repair shop?

Thanks

[LagerHead]

This is a computer problem of some sort. It might be throttle position sensor (though I doubt it) or something similar but it's going to be some kind of electronic, i.e. expensive, problem.

[peejman]

Agreed, sounds like a computer problem. Something is telling the transmission to downshift to 1st gear. Could be a bad sensor or damaged wire.

[Guest sayers]

I would check your gounds. Vw's are known for their electrical problems.

Go to www.vwvortex.com and find the fourm for your car. they the experts and probably have an easy fix for you.

[Guest db99wj]

Sounds like "limp Mode" I've heard of computers "shutting down" when their is an issue.

[KahrMan]

This is a computer problem of some sort. It might be throttle position sensor (though I doubt it) or something similar but it's going to be some kind of electronic, i.e. expensive, problem.

Agreed, sounds like a computer problem. Something is telling the transmission to downshift to 1st gear. Could be a bad sensor or damaged wire.

Thanks for the reply. That does make sense.

I would check your gounds. Vw's are known for their electrical problems.

Go to www.vwvortex.com and find the fourm for your car. they the experts and probably have an easy fix for you.

Thanks for the link. I have found a lot of good info there.

Sounds like "limp Mode" I've heard of computers "shutting down" when their is an issue.

The more I read at the link Sayers provided, it does sound like it is going into limp mode. It sounds like the N92 solenoid may be sticking. Need to do some more reading.

Thanks for all the replys.

[strickj]

Check your voltage regulator (alternator). When that goes out, it can make anything electronic go crazy.

The first sign of one going out will be dash lights and gauges acting up, including the PNRxx lights and tachometer.

Downshifting to 3rd will make the alternator turn faster (higher engine rpm) which may be why the problem corrects itself when she does that.

A faulty voltage regulator can cause false codes in other things like sensors because incorrect voltage will cause them to work improperly. so I would check and correct that before taking any further steps.

[KahrMan]

Check your voltage regulator (alternator). When that goes out, it can make anything electronic go crazy.

The first sign of one going out will be dash lights and gauges acting up, including the PNRxx lights and tachometer.

Downshifting to 3rd will make the alternator turn faster (higher engine rpm) which may be why the problem corrects itself when she does that.

A faulty voltage regulator can cause false codes in other things like sensors because incorrect voltage will cause them to work improperly. so I would check and correct that before taking any further steps.

Thanks for the tip. Will check that out first.

[Guest J.D. Skull]

Your problem is OBVIOUS. You bought a VW. I'll never make that mistake again.