Tiptronic Gearbox Problem

[cbr786]

hello peeps had a recon done on a 2001 996 c2 PRE FACE LIFT tip the car has all the power drives great in manual mode when I control the gears via the shift button on the steering wheels it changes up and down perfecty when i have control of the gear changes.

however the problem is in the auto tip mode it goes into 1st 2nd and 3rd & 4RTH at the right speeds and at the right time but will not go into 5th ?

its a wierd issue because if i drive really slowly the car goes upto fifth before I hit 35 mph in the auto mode then as I carry on acclerating at a steady pace not fast it slips back into 4rth and stays in 4rth even if the speed hits 100 mph it will not change up , If i use the steering wheel buttons I can press it upto fifth and then it will stay in fifth gear, and the dash gear indicator led will switch over to manual mode because i used the steering wheel buttons to push it into fifth, then as I slow down because I am not using the buttons to change down the gears on the car it will revert back into auto mode and the led will move back into auto mode on the dash so far so good, but as I accelerate off it refuses to go into fifth I have to maually put it into fifth by using the steering wheel buttons.

On my porsche I must have the later software on the ecu because in auto mode I can still use the steering wheel controls to change up or down with out the need to move the gear lever across to manual mode as I have to do in my other porsche which is a 1999 tip..

I have managed to get a good replacement ecu which has the same part numbers but is from a 1999 car this ecu exibts new symptoms when i plug it in its all very confusin ..

with the replacement tip ecu the car drives perfect in auto mode however it locks out the steering wheel buttons meaning i can not change up or down... when iI plug my original ecu back in the original symptoms return ..

I am wondering if the earlier ecu with all the same ecu part numbers has a different soft ware on it as to oppose my ecu ?

any help on the matter would be good by the way durametric soft ware says no fault codes anywhere on the car not even on the ecu

OPC said its an ECU fault and car needs a new ECU ???? could the 1999 ECU be differnt from the 2001 prefacelift model ECU even thought all numbers bosch ,ZF and porsche numbers tally up?....

[Loren]

Yes, MY99 Tiptronic control units are different part numbers than MY01. And, there were two different part numbers used in MY99 cars.

You car shares Tiptronic cotrol units only with other MY00-01 cars.

Sounds like your OPC needs to run diagnostics on the Tiptronic in your car with a PST2 or PIWIS tester.

[RFM]

It's the difference between Tiptronic and Tiptronic S, the Tip. S allows the possibility to shift with the buttons, while the gearbox is in AUTO, during 8 seconds.

[GranburyChuck]

How do I know if I have a Tip S? I have a 2000 996 C2 Tip and can shift up and down with the steering wheel buttons while in auto mode. After a few seconds if I don't shift it goes back to auto mode and operates normally.

[RFM]

If the gearbox react as you describes, than you have a Tiptronic S. The aim is to use the buttons, while the gearbox is in AUTO, instead of the kick down function, less brutal, faster shift time and more control/car feeling when up shifting (within 8 seconds)

[cbr786]

thanks for the input guys

fistly the dealer OPC ran the test with the tester plugged in whilst driving down the road and said they tried reflashing the software on the tip ecu but to no joy also they said they can only draw conclusion that I need a new ecu ?

also with regards to the tip and tip s answers I think this option to change gears in this so called 8 second window is only applicable to 2000 cars onwards ??

as I also have a 996 C4 Tiptronic S and that does not give me the gear change option at all in auto mode it stays in auto mode .....

and in manual mode i can change gears using tip buttons ....

but with the 2001 prefacelift 996 C2 (which is the car that is faulty) it lets me change gears in auto mode all the time when ever I touch the tip buttons on the steering wheel which to be honest is quite annoying as if you are driving and you touch the button by mistake you drop up or dwn a gear depending on which button i pressed by mistake .. and this function once pressed will stay in manual mode for about 8 seconds then flip back to auto mode if I dont press any more steering buttons..

it is confusing because I managed to get two ecu's from breakers unless both ecu's are faulty from the breakers they both dont cure my problem they make the car drive fine in auto mode but lock out the steering wheel buttons and when I flip the gear lever across to manual the led on the dash remains in auto and car drives in auto wont detect the switch over...

on an ordinary day you wud assume the switch on the gear lever to be faulty but this is not the case as when I put the original ecu back in it does detect the gear lever flip over to manual and auto etc hence it rules out the gear lever being faulty ....

the problem is definately ecu related but the two ecu's I have tried did not cure the problem ?

all the part numbers matched up on these ecu's the wierd thing is every breaker I contact confirms that the ecu came out of a C4 car and my car is a C2 yet it still has the same ecu ? surley the software would be different on C2 and C4 cars ?

[cbr786]

finally sorted it cost me some money so I am going to list it on this forum so other people dont make the same mistake as me !!

1)

first I gave it to an indpendant called ramus porscha in birmingham UK he spent all day looking at the car and charged me accordingly saying I need a new ECU he also suggested I change my n/s front tyre as it was the wrong size in the profile rating ?? to the o/s front tyre

2)

fearing ramus porscha had not diagnosed the car correctly I gave it to OPC sutton Coldfield Porsche in Birmingham who charged me £100 odd and told me that after looking at the car it required a new gear box ecu at £1400 big bucks,

3)

sourced an Ecu on ebay bought it and tried it but it would lock out my steering wheel buttons otherwise it worked fine in auto mode the car went into fifth

4)

wanting a cheaper option sent both ECU's the original and ebay one off to a Engine ECU specialist to check if anything inside the Printed Circuit Board was faulty they charged me £100 to say no faults visible although they have cleaned and re soldered some weak point so they say...

Btw the reason I sent it to an engine ecu shop and not gearbox ecu shop because thier are no gearbox ecu specialist in the UK with the right soft ware to test these gearbox ecu's any one claiming they can are lie- ing as the bench set up for this is very expensive and I tried lots of shops all said no one does it..

5)finally before ordering a new ecu from porsche at the price of £1400 with no warranty as it is an electrical part once sold it is yours no returns accepted blah blah blah!...

I decided to visit another independant D9 Autotech in wales bridgend.

first of all the garage was very clean niel and anthony the owners where very nice gave me coffee listened to my issues before going about to test my car what they found out with thier code reader was that alothough no faults where stored for both ecu's the ebay ECU came from a C4 car and my car was a C2 this is something I banged on about all the time to porsche and everyone else on this forum that the ECU i got from ebay had same part numbers as mine but was from a car that had 4 wheel drive it turns out that this ECU is compatible with my car because all the part numbers tally up!!!!!

what everyone failed to realise except for D9 auto tech was that my car has no PCM while the C4 does hence first thing they did was go into the ECU settings re configure the PCM setting to ABS setting after saving this setting hey presto suddenly the other ebay ECU which use to lock out the tip buttons on the steering wheel sudenly started to work ... however the car would still not go into fifth

so now I have two ecu's car drives fine but those not go into fifth ....

D9 Auto tech did not give up then they decided to investigate why the car would not go into fifth ....

the problem was that I had changed the tyre from the start as mentioned in paragraph 1 with a brand new tyre due to information supplied by ramus porscha this meant the thread dept on the n/s front tyre was 8mm as this was a brand new tyre however the thread dept on o/s front tyre was 2mm near the end life of the tyre to compound the problem further the rear tyres n/s and o/s where also different thread depts to each other ... 1.6mm and 5mm respectively ..

after changin all 4 alloys for another set with equal wear on the tyre threads for testing purposes we found that the car drove fineand the tip buttons worked and trying my original ECU same thing car drove fine and changed gears as it should my problem was tyre thread depts where wrong ....

thats all pure and simple wrong tyre depts sent inaccurate messages to the gear box ecu via the abs sensors causin the car not to go into fifth gear ....

very important all tyre pressures and tyre depts have to be equal other wise tip tranny starts to play up

I could have save a small fortune if only the OPC and the first independant diagnosed the car correctly which they did not .... hope this information helps some one else out there with tip probs to cure thier own car ...

thumbs up to D9 Autotech they are over 150 miles away from where I live but where worth the journey as they are very friendly and do not charge the earth resonable rates £35 per hour at the moment ...

[cbr786]

oops typing error I think I meant PSM instead of PCM its some sort of stabilty program that comes on porsches as an optional extra or as standard on C4 and not on C2 cars

[CosmosC4S]

Wow, cbr...that was quite an adventure! Thanks for posting and I'm glad you finally solved the problem.

[dgpfxxx]

wow. I have the same problem, and today i just changed one tire. Im gonna have to buy another one lol. I thought i needed a new tranmission :o

i have a 97 boxster, and it just didnt get into fifth..

[dgpfxxx]

Update 2010 feb, i just changed the two fronts to new tires, the car changes gears fine. Jeez i thank cbr786 for this article, i didnt waste all that money.

I am really happy, because i was thinking my solenoid was bad.. PHewww.

[996max]

Thanks for the post, good luck to you.