Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

hey guys, this is my first post in hopes of coming to a conclusion, i currently have a 1998 porsche boxster with tiptronic transmission, the following problems are as follows.

1.when in parking the car doesnt stop

2.when in automatic drive car doesnt go to 3rd gear it jumps from 2nd to safe mode with a big kick

3.when left on first gear in manual mode car exhaust sound gets louder, and when letting of the gas does big kick to safe mode

4.when the car is turned on and switched to manual the tiptronic controls only lets me move up to 2nd gear.

i was thinking it was the transmission ecu but it wasnt, i have tried 2 other ecu's one with the exact serial codes as the original (besides actual ecu serial) and still same problem

Might it just be the transmission itself?

if so where can i buy rebuild parts?

and guide on how to.

I really need to get this figured out any advice would be helpful, thank-you for your time :)

Edited by Nivaldo Veliz

Share this post

Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

I have two suggestions, perhaps it might be worth checking that the linkage is properly aligned, secondly I have heard of tiptronics working in manual but not in tip mode as a result of a clogged transmission filter. These autoboxes are reckoned to be very reliable so I would look elsware first before considering exchanging the gearbox.

Share this post

Link to post
Share on other sites

P0722 (Porsche codes 36 and 90) Speed sensor - signal implausibleTransmission output speed monitoring - signal implausible

P0722 Open circuit(Porsche Short circuit to B+ code 36)

- Short circuit to ground- ATF level not OK- Faulty torque converter- Slipping clutch or brakes

P0722 Open circuit(Porsche Short circuit to B+ code 90}

- Short circuit to ground- ATF level not OK- Slipping clutch or brakes

Share this post

Link to post
Share on other sites

does this mean that the sensor itself might be ok? and giving code because of one of those ^ ? also, where would that specific ground cable be at?

Share this post

Link to post
Share on other sites

I have had similar issues and may be able to help guide you down this path a little bit. How was it driving before these issues? Any noticeable changes in shifting performance?

As Loren noted, most likely scenario is low ATF, but most people will notice a significant leak if this is happening. Regardless, this is the first and easiest thing to check. If ATF level is ok I would look at your coolant reservoir to see if there is any sign of oil/coolant intermix in it. If so, it will look like a creamy coffee color, or you will see oil floating on top of the coolant. If this is the case then you have a blown ATF cooler which will need to be replaced, followed by seriously cleansing the transmission of all intermix. Hopefully this is not your issue.

Also, check the appropriate pins for correct short and ohm readings both at the transmission (round plug towards the front of the ATF sump pan) and at the ECU. This should confirm if your sensor(s) are out of range. If you don't have these values, let me know and I will track them down and post them. While at the round plug check to make sure that oil/water has not seeped into the wiring.

There is at least one pin in the plug that is for ground, but you will need the pin diagram to find it. I can post this as well if you need it. Alternativey, use a very long ohmmeter probe and attach it to the negative terminal of your battery.

Basically, the code you reference will be issued if the expected wheel speed is not obtained at the given RPM. Once the CPU sees this, it will issue the code and put the transmission into default mode (flash P and 4) to protect the transmission from any further damage. Yes, this could be a mechanical transmission issue, but I wouldn't jump to that conclusion yet.

I am in the middle of rebuidling my transmission after a failed ATF cooler and resulting intermix that demolished the fiber clutches in my transmission. There are several sources for kits for rebuilds, but again, don't jump that far yet!

Share this post

Link to post
Share on other sites

If you have a proper scan tool you can read the rpm of the transmission speed sensors but low fluid levels will give bogus readings so that has to be addressed first. You also need to verify the multi function switch is indicating the gear box is in the correct gear. These are fairly reliable gearboxes with two main points of failure is the torque convertor bushing failing causing a oil leak and the coolant control system for the cooler as another.

Share this post

Link to post
Share on other sites

ive done some research, its most likely the inductive transmitter on the valve body AKA (output speed sensor)

Edited by Nivaldo Veliz

Share this post

Link to post
Share on other sites

Certainly possible. Should be easy to confirm with an ohmmeter that the sensor has the correct value.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By Garra671
      Tried googeleing it but couldn’t find what I was after.    Was curious if anyone knows what type of flat 6 the 986 boxster has?
      Is it a a true boxer engine? Or a horizontally opposed flat V?     True boxer meaning it has individual crank pins for each piston and is a true 180degree angle.    Thanks in advance 
    • By 01BoxterS
      The rear window on my 2001 S has separated from the canvas, and the tan top is dingy and past its prime. I no longer have a garage, so I am forced to outsource it. I would appreciate some informed opinions.
      I'm looking at a GAAH A5 Acoustic glass window top. The dealer is saying $2,700-$3k installed. A reputable convertible/interior specialist is coming in at $2,200. The dealer talked about needing to buy additional sound insulation, clips and etc., which is either building in additional profit, or it may be totally justified because they have experience and might provide additional quality. I don't have an excess of cash for a 18 y/o car so I'm soliciting experienced opinions:
      Assuming the local top specialist is truly skilled at their game, should I expect that they can handle this, along with connecting the heating element?  I doubt they have done many A5 Acoustic glass retrofits, whereas the dealer has likely done a few. If I go with the local specialists, are there some unique things I need to specify they order/replace/pay attention to? Should I give more weight to (a) Porsche dealer that only occasionally does a top or (b) the people who do tops all the time, but just not Porsches?    
      All informed opinions are welcome. 
    • By Garra671
      Recently I had been noticing issues with my cooling system the coolant temp guage would go past the 0 on 180 and I wouldn’t hear fans or anything. (Already tested fans and resistors and relays).   The temperature Will continue to creep up if I sit still, with no signs of fans, AC OFF.

      I replaced the coolant temp sensor. Problem fixed!! Then same issue again it seems after a week of driving.  

      Now i currently have ordered another temp sensor just Incase I maybe did something to cause the other new one too fail, I’ll be changing it again today.

      However I was doing the climate control hack to check my actual temperatures today while doing a short troubleshooting drive. And I noticed my oil temperature said 0, which is physically impossible 🙄

      Is it possible the oil temp guage is throwing off the coolant sensor?    Is it even possible for the oil temp sensor too go bad but not the oil level sensor? (They are a 2 in 1 sensor)   

    • By Bardia Manafi
      Hi all, just purchased a 1961 notchback 1600s, I have never drove a Porsche until the day I purchased this car, got the bug now and i love Porsches more than ever now, the car is in very good shape, but i want to change all the fluids, grease all the parts, and do all the maintenance there is, the oil was so dark when I checked the level and it was all the way to max line of the stick, i would appreciate if you guys can tell me where to buy all the maintenance parts, and where can I buy the shop manual, and what are the things I should do, there is a small leak on the floor from engine very small, but a palm size of oil from transmission on the ground,  thanks guys cheers😁

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.