On-board computer control lever and speed control lever not working.

[mthunwardsen]

Okay, thanks to everyone for their help in advance. I did several searches and turned up nothing so here I am.

I have a 04 996 TT

So I had the instrument cluster out and disconnected the gray, blue and green connectors, along with the removing the hazard switch from the relay that it mounts too. I put everything back and even re-did it to insure that I hooked everything up right. These levers definitely worked before. Now both the computer control lever and the cruise control lever are not working, and by not working, I mean they do nothing. I also had then center console area removed, but I don't have the stock PCM anymore, so my best guess is that did not have anything to do with my problem (I was mounting a microphone for my bluetooth/aftermarket head unit). The instrument cluster appears to be in good working order, it is just unresponsive to these two controls. This smells of something stupid. Like I said, everything else appears to be in good working order. Could this be a fuse issue? I will check that tonight.

Thanks again for all your help, you guys are the best.

-Matt

mthunwar@hotmail.com

Edited February 1, 2010 by mthunwardsen

[mthunwardsen]

Anyone have any idea's? Thanks.

[Loren]

Not sure - it could be that OBC needs to be reprogrammed (with a PST2 or PIWIS tester) when no PCM is present.

I have never tried - but that sounds logical.

[mthunwardsen]

Not sure - it could be that OBC needs to be reprogrammed (with a PST2 or PIWIS tester) when no PCM is present.

I have never tried - but that sounds logical.

Thank you for the advice. Is there are way to reset the OBC to factory default settings? Maybe like unplug the battery and turn on the headlights for 10 seconds then hook up the battery again? I know that works for other makes. Also, I wanted to be clear, I haven't had the PCM in there for a while. The OBC lever and cruise lever work up until just yesterday. Thanks again.

-Matt

[Loren]

Ok - I thought you said this happened when you disconnected the PCM?

Do your brake lights work? If not check fuse B7 - stop lights, cruise control.

[mthunwardsen]

Ok - I thought you said this happened when you disconnected the PCM?

Do your brake lights work? If not check fuse B7 - stop lights, cruise control.

Brake lights work. Now what? I will keep searching around. Thanks for the advice.

[mthunwardsen]

Could this be tied into a relay somewhere? I am searching for a wiring diagram and I am not having any luck. Can anyone point me in the direction of one? Thanks.

[Loren]

Check the fuse I suggested and if it is okay then I think you need to put a PST2 or PIWIS on the car and find out what works and what does not.

[mthunwardsen]

Okay, B7 checked out okay. I feel ignorant for asking, but what is/are PST2 or PIWIS? Are those diagnostic tests or test modules? Can I do this (perhaps through an aftermarket code reader or something???) or do I have to go through Porsche? Thanks again for all your help.

-Matt

[Loren]

PST2 and PIWIS are Porsche test computers. Many good Porsche shops have both or at least a PST2 (older of the two).

I have both and if you live near me I'd be happy to put one on your car and see what is going on.

[Richard Hamilton]

Is your car manual or tiptronic? Coupe or cab? Does it have park assistant?

If it is a manual coupe without park assistant, then the only things connected to the grey plug of the instrument cluster are the cruise control and obc stalks. I would triple-check that plug.

[mthunwardsen]

Thanks for the offer Loren. I live in Simi Valley, Ca. which is probably a 7 hour drive from you.

I think I may look into the grey connector issue. I have a manual cab, but my grey connector is broken on the back end. It has been that way for a while, and I did not think it impacted the functionality of the connector, but may be. I will play with it tonight, and maybe upload some pictures if I can.

Thanks for the suggestions, I will try them tonight.

-Mattt

[mthunwardsen]

BTW, what does it take to replace that grey connector on the back of the instrument cluster? It looks pretty integrated into the wiring harness. Thanks.

-Matt

[Richard Hamilton]

I think this is the part, and the VW part number is shown. If the internal white part of the connector is intact, then it would be a simple matter to change the outer part and locking lever. I think someone else posted the Porsche part numbers on here a while ago, so it might be worth doing a search.

[Loren]

BTW, what does it take to replace that grey connector on the back of the instrument cluster? It looks pretty integrated into the wiring harness. Thanks.

-Matt

Most of the problems with this connector are either it is not seated proper and latched into place, or someone pulled to hard and broke a wire, or a wire got pinched in the console when they put it back in place.

I would verify all of those before I went to the trouble to replace the connector.

[mthunwardsen]

Okay, checked out the connector. The portion that was broke was the strain relief portion of the connector. I was able to remove the grey outer sleeve and mechanically check all the wires in the connector. All checked out fine (pushing and pulling). I put it back in and still no OBC or cruise. I guess I need to get it checked out. Just afraid of the dealership, read so many horror stories of dealers bending people over. I will just have to bite the bullet and take it in. I need to get my secondary key cut and the fob programmed anyways. Kill two birds with one stone I guess. Thanks for all the help, and if anyone thinks of anything, let me know and I will try it.

-Matt

[mthunwardsen]

Here is another idea. Where does the other end of the wiring harness for the gray connector hook up too? I can't see without taking the whole dash apart. First off, I would like to check the pins on the wires going to the gray connector to see what sort of signals/voltages I am able to see/read. I am an engineer (Laser Physics) so I have some experience with wiring diagrams and circuit diagrams, but I am by far not an expert. I have a volt meters and an oscilloscope. Does anyone know what sort of voltages/signals I should be seeing at the gray connector?

Thanks

-Matt

[Richard Hamilton]

YHM

[mthunwardsen]

Thanks everyone for all your help. I found the problem tonight. I appears that Loren was correct, after I broke the gray connector housing and it appears to no long make a good connection. I removed the gray housing, and just plug the sub-connector into the instrument cluster and bingo. This is not a permanent solution, so I have to get a new gray connector housing from somewhere (Sunset???). It looks like an AMP part: 3-929409-1. I assume the Porsche part number is: 999.650.509.40 which is right below the AMP #. On the other side there is another number: 3-929407-1- and then below it is >PBT-6F20< I think I am going to try and find the connector now. Thanks everyone for your help, and anyone who knows where I can get it, I would greatly appreciate you passing that onto me.

Thanks

-Matt

[whall]

Matt,

BROKEN PLUG HARDWARE. For those MY01 – MY04 DIY’ers who have broken the lock on one or more of the instrument cluster plugs or who are afraid they might, here’s the part number you need : PNA 721.04.300.202. This part number gets you a package with the three colored (blue, green, gray) covers/locks and all three black plugs. They only come as a set of three and cost $27.00 (dealer). The blue, white and black covers/locks and plugs are available for MY97 – MY00 Boxsters too. Have your Porsche technician (not parts guy) check his “Porsche Electrical Connector Repair Kit” for the replacement parts or at least a part number for the three plug package. The entire repair kit is known as CARTOOL – Nr 96 0 000 or PNA 721 043 600. It is full of connectors the parts guy would like to sell you the entire wiring harness for.

Unless you can get a used part from a breaker's yard or from a sympathetic Porsche technician, you'll probably have to order the entire set from some place like Sunset.

Bill