Strange Tiptronic action, advice sought.... thanks!

[berni29]

Hi

I have cross posted this in the 986 forum because of the common Tiptronic gearbox.

I recently had my box out for an IMS etc. Since replacing I have had a flashing "D" (not the D & 4) for the first couple of minutes when cold. During this time you cannot switch the car into manual mode, but all the gears work fine using the buttons. You would not know there is anything abnormal apart from the following.

As the flashing "D" stops and the display switches back to normal (ie showing which gear you are in) the car looses power/drive for a second, but not always. Then it works great.

The gearbox fluid level is almost certainly correct. I even added some to see if it made a difference, but no. I then let the extra out. Still no difference.

The Durametric shows no faults.

Any ideas?

Thanks in advance

Berni

 

[kas750]

I do know that oil type and quantity is absolutely critical in these boxes and near enough is not good enough.

 

[deMort]

Not uncommon for these and 996 .. actually 997 as well to have issues with the multi function switch pack .. the bit on the gearbox with the wiring going to it !

You will often get a fault code for it though .

A stiff gear lever can cause similar issues as the position of the gear lever at the front and the rear are slightly off .

The push rod on this switch can also pull out from the ball joint ends causing a difference .


Cant say if it's your issue but it's something to bear in mind .

 

[berni29]

Hi

Well, I had the car level and used an infra red thermometer targeted at the sump. I have heard people say it takes quite a few minutes to get to the 30-40 deg C required for the fill, but in my car it did not take long, and quite quickly moves past the 40 deg C level.

I pretty much emptied the whole system so the fill was almost 9 litres. I did mix two fluid types though. However I did research it and they are miscible. Plus the fault is on starting and seems to be temperature related so I'm sure its not related to fluid performance. I drove it 40 miles or so last night on fast roads and not a hiccup.

Hi DeMort, I am sure its not the linkage being out of alignment. I was quite careful with that. Also the switch was replaced just before I got the car and looks new. Not that it is not impossible it has an issue. I also used plenty of contact cleaner.

Do you know what the flashing "D" means? Just a general "not happy!" probably. I know the flashing D and 4 is a different kettle of fish. I did have that once after the very first fill.

Berni

 

[deMort]

Flashing D to me means limp home mode , box has seen an issue and has reduced gear change and possibly engine power.

I thought it was D and gear position 1 or 4 that flashed but its not something i've taken note of .. i just look at fault codes im afraid .

See my post on engine running issues .. it might be linked to the maf being faulty .

 

[berni29]

Hi DeMort

Having fixed everything engine wise, I am left with the some conflict in the linkage system as you suggest is possible.

Are there any microswitches in the gear lever mechanism? I could not see any on the PET. How does the selector up front talk to the switch down back?

Many thanks!

Berni

 

[deMort]

These work differently depending on the Porsche model so i've looked at a diagram .. it seems to be a basic switch setup ..

It merely as best as i can understand knows park or neutral position .. if the multifunction switch reports the car is in drive then there would be a conflict and presumably a warning on the dash .. flashing D perhaps ? i'm unsure .

Switch lifting being the multi function switch with selector lever obviously being the selector lever

You have an issue with the car not running so logically its a conflict between these .. i'm not sure how you would test them though ..

Box out and then fault happens so i would be looking at the wiring plug on the box , plug on the multifunction switch and the cable adjustment ..

Cable adjustment is high on my list to be fair ..

Check plug pins as well .. not hard to bend one and so have no connection .


Its possible the magnet is merely for when you put your foot on the brake to release it .. don't think that works in neutral though and there is a cable from the ignition lock for the mechanical connection .

 

[berni29]

Hello!

Thank you that is food for thought.

I had a good look at the linkage today. The only switch at the gear lever end as such is the one that registers when it moves across into manual mode.

I lubricated the mechanism front and rear, and checked that in park and drive there was no tension on the cable and selector mechanism at the gearbox end. IE that the multifunction switch was cleanly in its detent.

Earlier in the day the gearbox glitched quite a few times after the car was reasonably warm, so there is less possibility that it is temperature related. Then the rest of the day it was perfect.

I will have to check the connector again, but last time I cleaned it well and wrapped it in loom tape and then heat shield material. So I don't really fancy getting it out again.

Lets see how it is tomorrow morning. Fingers crossed.

Edit: I really hope the switch has not failed again.

Edit: Apparently on the PIWIS2 as you select Park Drive etc, the PIWIS confirms it and if the switch is glitching it shows an extra letter in between each selection. I will try and look up the post that describes this.......

Thanks again

Berni

 

[berni29]

Hi

Just a quick update on the gearbox issue.

I readjusted the linkage, which it did need somewhat. No change in symptoms as such, although it did seem to have a positive effect.

If from cold I do not start the car and instead put it in drive "D" then turn the ignition off but leave the key in (and the lever in drive) the "D" light will continue to flash. Then after a few minutes (less than 5 but I have not timed it exactly) the "D" will stop flashing.

If I then start the car it will drive normally for the rest of the day.

If I do not wait for the "D" to stop flashing and drive the car then the glitching continues until it does (edit: stop flashing that is).

How strange is that?

Berni

 

[deMort]

To be honest .. i have absolutely no idea !!

To adjust these though .. put the gear lever in park , put the gearbox in park ( rod disconnected ) .. if the ball joint lines up exactly then that's the correct position .. a slight tightness either way and you need to adjust the rod .

Other than that i'm back to my first comment .. it doesn't make sense to me ..

The downside though is i will be thinking about this all damn weekend now !!!

 

[berni29]

Hello De Mort

Thank you. yes, thats exactly what I did, ball joint at the rear of the linkage split and then adjust until fitted cleanly on the ball.

Its certainly a conundrum. Funnily enough I went to time the flashing this morning and it didn't! It was pretty warm out though.

Will check again tomorrow.

Thanks again!

Berni

 

[berni29]

Hi, Update on this.....

After the linkage was adjusted all was perfect until 3 days ago, then when while driving towards the Blackwall Tunnel the car glitched, and then the 4&D lights started to flash and the gearbox went into limp mode. Made for a nervous drive through the tunnel.

Now on starting only (not with the engine off like I used to get with the flashing D) I get the flashing 4&D, or 4&P, or 4&R, or 4&N lights regardless of anything.

The gearbox is throwing no codes, tested with my Durametric and generic reader, and is constantly in limp mode.

I have put a new Silver Bosch S5 (from my 993) in, but no difference, apart from the engine turning over much faster.

I am guessing it must be the "multifunction" switch.

Has anyone had one of these things apart to see if they are fixable by the creative home mechanic (bodger)?

Edit: Gearbox works as expected in limp mode. No slipping or top gear, thumpy going into reverse.

Thanks again!

Berni