Porsche Enthusiasts Club Forum

Hi all
I have a bad TPS sensor on my Porsche 944 turbo. These parts wear like many cars due to the use of a carbon track as the potentiometer which will wear over time and can see premature fail due to oil or dirt ingress.
Now the easiest this is obviously to replace it as it is a wearable part. Some cars with similar applications have replaceable TPS units for around £50, but this one is about £300.
I don’t want to spend that sort of money for an old design when there are improved solutions out there.

Modern cars use a contactless magnetic solution that changes resistance as a magnet turns on the shaft. This gives more accurate readings and won’t wear out.
Does anyone know more about this and how to repair mine with this? I’ve found a lot of companies selling the magnetic solution which I’d have to adapt somehow but I think the key is knowing the resistor values to set up the contactless solution correctly.

Please let me know if you know how to get the correct resistor values or if you know how to replace with the contactless solution - I know people do this for Maserati TPS with the same fate but the procedure is a well kept secret.

Have you tried running the car with the TPS disconnected?

Yes it gives a high idle and a rich mixture.
Other than the microswitch which is working, which tells the car when it is on idle and the throttle is shut, my TPS is giving no reading at all - the track is completely worn away.

I've contacted a few companies about a contactless solutions and all have told me its possible but the calibration effort isn't something they want to take on. It is really interesting reading so I'll summarise what I've found in the next few days.

Google is your friend,
https://rennlist.com/forums/944-turbo-a ... ies-2.html
http://www.arnnworx.com/catalog/index.p ... &chapter=1

Thanks for sharing. I'd already read those and sadly don't help me.
The arnworx one is resolved by cleaning whereas mine is worn.
The other post offers a solution for the NA car but not the turbo. Finding another TPS that fits is only half the problem - the resistance would have to match to send the right signals to the ECU - sadly the NA one is only about £30 and the turbo one is £340ish.

the TPS is a Bosch part and the same one is used on the Volvo 440 turbo,

stop searching for the Porsche part and start searching for the Bosch part number, you might have better luck

0 280 120 400 thats the old number, the new number F 026 T03 070



£161 Mr Auto

I suspect the ****** that are charging nearly £400 have paid less than £160...

Thanks, for taking the time to look.

I’d already searched the Bosch part - it’s used in a Volvo 440 and 480 turbo.

That mister auto is just an intermediary and the part listed isn’t available. I’m sure a few years ago it was £161 but I doubt Bosch are making any more so suppliers are slowly increasing the price.

I’ve emailed a number of companies performing the upgrade to magnetic hall based potentiometers and they do it for other cars but so far noone is keen to take on this project as the testing and calibration is too time consuming and ultimately isn’t worth their trouble - that being said it can be done and has been for very similar cars.

you could buy it from over the pond

as im sure anyone that has to build and calibrate what you are asking for will charge far more than £400

https://www.germanautosupply.com/bosch-f026t03070.html

http://www.bosch-classic.com/en/interne ... ser_1.html

Thanks,

I may have to. I wanted to explore the possibility of a contactless solution as these are getting more costly and it’s a bad archaic design. It would benefit owner in the long term if we could get a permanent solution