Marine Blue

So the RDK on the 90 was disconnected and I want to have it back since I'm lazy about checking tire pressures.

I've put the pressure back up in the tires and I want to reinstall the RDK so everything is operating. I found the connection underneath the dash and I removed the jumper cable on the loose connector. Is there a jumper that I should be searching for anywhere else? Also what the heck is the trick to reconnecting the thing. I tried plugging it back in but it doesn't seem like it's all the way in and I can pop it off to easily.

Anything else I need to do to active it?

borland

The controller is easy to remove from under the dash. I'd suggest you do that before reconnecting the connector. With the controller and connector right side up, it should be a snap to reconnect and test.

Marine Blue

Thanks Borland. When I was contorting my neck to look under their I thought "there has to be a better way!" Problem is that I misplaced Jim's CD's when we moved last year and now I'm left asking these amateur questions. Can you describe how to remove the controller?

928Myles

The controller is held on by a few screws/bolts by memory. In my 90 S4 the seat memory control is mounted on the top of the RDK.

I found it easy to remove once I had managed to twist myself into position.

I would expect that the system was disconnected due to a fault so may not work propoerly anyway.

Best of Luck,
Myles

Marine Blue

Guys thank you for the help, seriously appreciated.

So I contorted again to find two philips screws holding on the RDK System. I removed these and it popped right out. It took me a minute to figure out how the two mated together but once I did it went back together fast. I fired her up and the system is now active and working.

ColinB

Myles.
Your car is presumably RHD. The RDK controller and several of the other 'brains' are in different locations in LHD cars.

Afshin
If the system is active and working (properly?) you have a rare beast there. You'd have to wonder why the thing was bypassed in the first place. I'd really like to reactivate mine but I know it's a lost cause. I tinkered with it for months before I finally conceded defeat and fitted the bypass. Personally I think it was Herr Dr Porsche's private joke.

Luck with it.

Colin 89GT (RHD)

Marine Blue

Hi Colin,

Yeah, I do feel lucky that it's working. When I pulled the jumper the car notified that the RDK was deactivated and after connecting it the warning was off. I'm still not sure exactly how the system works, for example does it offer real time pressures or just an alarm when pressure gets too low? I have to read this but I seem to find mixed information on previous threads.

The previous owner disconnected the system because he prefers to run lower pressures (32/36) and the system would constantly alarm. I actually prefer the higher pressures (had the same on my last car) so this worked out for me. My only worry is that the recommended pressures on the tires are lower than the cars recommendation.

I haven't driven the car yet to determine if the system is operating without issues so I will have to report back but the initial test and startup were fine.

ColinB

Ah, that would be one reason to bypass a working RDK of course. Never thought of that.

The RDK system displays a schematic diagram on the instrument panel warning bar to indicate which tyre has lost pressure. The actual pressure in the tyre is not displayed. It doesn't work at a standstill. the car has to be driven about 20ft before the system activates. If you have the manuals there is a comprehensive section on the RDK system. If my notes are correct it's Sect 44 Page 21.

Colin. 89GT.

bigmac

Mine gave a warning after any weather front came through town. Good luck!

Marine Blue

Cool, thanks!

Also appreciate referncing the pages in the manual, I have to admit I've only read through about half and focused on the areas of this car that differed from the S4. I seriously didn't have any idea just how much Porsche changed in such a short span. I will read up on this more tonight.

Marine Blue

LOL, like Arthritis huh!

If it's that sensitive I may be disconnecting it again.

Rob Edwards

Maybe I got lucky, mine worked perfectly (when the tires pressures were set at 36 and 44) until I switched to Heinrich's 17" Cup rims. I have a set of the brackets used on the '93GTS to move the sensors out 1/2" or so, but I haven't had a chance to install (will do this along with the brake lines soon)

Vilhuer

Porsches design is bad in a way that there is no way to adjust pressure when alarm is shown other than changing actual sensors. Tire technology has moved on since late eighties and neede pressure has come down several tenths of bar. S4, CS and GT have different sensors at front and rear. Limit is 2.5 bar for the front and 3.0 for rears. GTS use 2.5 bar sensors on all four wheels. Installing 2.5 sensors to 16" rear wheels would help a little. Ultimate solution is to integrate some aftermarket monitoring system to Porsche control unit and make 928 think its seeing stock sensors.