At Law

Just curious how the power trunk release works.

If you are rolling at all, even out of gear with the clutch engaged
at very low speeds, the power trunk release will not work.
Once you come to a complete stop, the switch will open the trunk.

I could understand if the trunk would not release when the car is
in gear. However, how is the car programmed to understand when
the car is moving to not allow the trunk switch to work?

Edgy01

These cars have all sorts of motion and yaw sensors in them as part of the suspension system. It would be quite easy to use one or a combination of their inputs to tell the trunk release that the car is still rolling. If you don't buy that, just remember that's all FM. (Just like it tells the car to put up the spoiler at 75 mph ACTUAL vice indicated).

rijowysock

im guessing just a speedo sensor, my old S2000 had a speed sensor for the convertable top, if u pulled one wire behind the dash u could put the top up while rolling.

brendo

^ how did that work out for you?

rijowysock

worked fine, just couldnt go more than 20 or so..

i loved my 997.1 because u could put the top up/down up to 55mph... helpful in the rain.

Edgy01

"On the ABS generation 5.7, a new active wheel speed sensor generation (DF 11 type) was introduced. This sensor has a Hall element and an IC (Integrated Circuit). In comparison to the passive speed sensor, the active speed sensor generates a variable pulse width square wave signal. This technology not only determines the wheel speed, but also the direction of rotation, wheel stop, and the signal quality."

Fron the workshop manual.

robbonds

You can put the top up going 50???

winkingchef

I think you means kph. It must be those damn Canadians poisoning your mind.
My 997.1 C4S Cab will only raise it's top going 29mph or less.
...unless you had a Targa....

rijowysock

I think at 55 it stops you. But up till there works fine. I did it hundreds of time at speed without any ill effects. It's programmer to stop at 55 or so, so obviously they tested it and put a limit for a reason.

I loved it. 45 on highway starts raining and you put it up on the go.

rijowysock

I meant mph. I had 997.1 cab. Up or down. Up I remember it popping a light at me around 50/55/60 it's been a while. Down was the same. Try it. My997.1 was not modded to do such.

robbonds

wow..i thought it worked up to 30 or 35...can it get damaged at 50 ?

JW911

If you have Smart top upgrade it works up to 45mph. No more than that. 46 or more is not possible. If you don't have Smart top it is much lower. I think 30 mph or so. Can't remember exactly (I have Smart top).

rijowysock

so the owner before me must have installed something? i had K40 hardwired, must have had something else as well i never saw.. that red blinking whatever it said on the cluster didnt come up till very fast... i havent had the car for 6-7 months so i dont remember exact speed but was faster than 30 for sure. i guess 45 might sound right...

makes me wonder if it did other stuff like top down from remote.. i always wanted that!

OldGuy

The trunk release is a simple servo type of motor on the trunk release. That is controlled
by the computer, and probably has test scenarios where the computer will not allow the signal
to go through. The computer is sensing a millions sensors on the car and making decisions every
millisecond. Once the car gets to a certain sensed speed it probably turns off certain sensors,
like the trunk latch, Cabrio top etc.

Just an example an F-18 C/D models Mission Computer polls all its Remote Terminals
every 50 milliseconds on whats called the 1553 Avionics bus. So in that cycle it will have talked to the Comms, navigation computers and even
the Stores management computer. The Stores management computer is in charge of all the weapons on board. The Stores computer talks to its weapons via another computer bus.
I am betting the BOSCH ECU has more than one processor, and its obviously some type of programmable chips. I am also confident its faster and more modern than the F-18 Mission computer.
The new planes like JSF are using more modern communications like 1394 and several other standard com Serial communication systems. JSF has a bank of primary computers not just one dominant computer. I was surprised that it has multiple ways to talk instead of one
main communication bus.
It would be cool to see how Porsche and Bosch accomplish the computer processes.