Porsche diagnostics

PC based Diagnose Tool UDT999

Ready to take your order !!!!

Initially designed for 928,

now compatible with 944, 964, 968, 993, 996

Ok, we started this project as something completely different: LH ecu repair. Because we were severely short on diagnostic tools and the Bosch Hammer was hard to get and seriously expensive we started another project: build a PC based diagnostic tool. It must have all the Hammer functionality and *more*. I do this project together with my friend Paul. We both own 928 and have an electronics background. Paul, by buddy, is tremendously knowledgeable and takes credit for most of the work.

This page shows some of the screens and stuff related to the project. Since the project now finished (do projects ever finish?) we decided to announce the product and see if people are interested in buying our tool.  We plan to add still a few more new features to our diagnostic tool, so there's more to come. Best of all: it is free upgrades for the Windows based version !! 

The product that we offer contains:

  •  interface module that connects the 928S4/GT/GTS, 964, 944s2, 993, or 996 to a Windows PC Laptop, or Windows based Tablet
  •  interface connection to the Porsche 19pin diagnostic port and to 16 pin OBD/OBD2 style  port. Optionally we offer an adapter to 12pin port in a 1987/1988 928S4 or some 944S2.
  •  software that communicates to your interface module
  •  extensive documentation of the Porsche diagnostics tool
  •  multi lingual user interface and messages (English, Dutch, German, French)
  •  free software and manual updates for any registered buyer (via download)
  •  Win11, Win10, Win8, Win7, Vista, Xp ? No problem, all supported. Users also have our tool on MAC with Win emulation s/w (we do not support this but it works).

To give you a real good insight of our product, you can download the MANUAL from our server. We encourage you to do so. It's free. Please, navigate to our  web server via webserver ,  create yourself an account if you have not done so already. You will find the latest documentation and also get access to our forum for the latest news.
Check out our demo video's

Installing UDT999_1.mp4   Using UDT999_01.mp4

If you have a 1987/1988 model with a 12pin rectangular diag connector, we offer an optional 12p cable that we have manufactured especially for this purpose. The same is used in the 944S2. The UDT999 comes standard with a 16 pin OBD2 style connector and an adapter for the Porsche 19pin round socket in 928, 964, early 993 and other models. 

Check the pricing in our webshop. Please allow up to 3 weeks order to delivery lead-time. We accept IBAN/BIC international bank transfers and credit card payments via Paypal (a 5.5% surcharge fee for Paypal applies).

Please contact us via email to place your order of use our webshop at this URL:  webshop. If you have any questions, please do not hesitate to contact us.
kind regards,
Paul and Theo
928-diag (~ insert a character ~) jenniskens . livedsl . nl  or 928-ecu-repair(~ insert a character ~) hetnet . nl or on our Webserver at: http://webserver.jenniskens.eu


This software runs on any windows PC, and the latest GUI version is also wonderful to use on a Touchscreen Tablet PC

We offer two versions of the software. These are pictures of the early design that is still available but no longer in maintenance:

This is the current GUI design. It is easy to handle, ready for touch-screen, and compatible with the latest windows updates:



12pin rectangular connector at the 1988 models (possibly 1987 with firmware upgrade)


And we offer LH repairs. We designed our own replacement pcb for the failing hybrid circuit inside the LH.

Here is the one from my own ecu. It still worked after 15 years, but I did not like the thought of getting the car home on a flatbed.

Imagine yourself on the phone to call for assistance. The LH *will* fail on you. Just a matter of time.

Contact us fro more information and price.


Handheld Diagnose Tool :

Portable Diagnose Tool PDT999

After the success of the (PC based) DT tool range, people ask me to build a handheld device like the Bosch Hammer KTS301.


Read ECU's from 928 (S4/GT/GTS) / 944 S2 / 964 (C2/C4) / 968 and 993 (with round connector).
Large 4x20 characters display (57 mm x 20 mm).
White characters, blue background, backlight.
Complete menu controlled.
Only four buttons: menu-up, menu-down, select/back and OnOff.
Standard connection to the car.
Long cable with 19P connector.
Supply voltage from the car.
Dimension box: 185 mm x 85 mm x 28mm.





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