Swapping DME, matching key and inmobilizer

[smartrepair]

Hi

I have a 98 Boxter with 3.4 engine on it. Suddenly the car doesn´t start. First the car was cranking, but not firing. Now it doesn´t even crank.

With Durametric I got the following codes:

49 k line

10 no current at 30

36,34 and 33 interior senor

42 not correct key or transponder

23 w line

47 locking syncronizing

21 inmobilizer line w

It´s difficult for me to bring the car to the Porsche (long distance), could I use the DME, and matching key transponder/inmobilizer combo from other car? I found one, that is from year 2000 from 996 to swap them over ? This RoW version, and my engine is a RoW as well. The inmobilizer in my car has value M535, and the combo for sale has M534.

Many thanks in advance!!!

best,

Kare

[Richard Hamilton]

The immobiliser uses the diagnostic line (W-line iirc) to transmit the immobiliser code to the DME. If you have the wiring diagrams, you will be able to identify which wire it is. On a 996 there is a plug and socket in the rear footwell that this connection runs through. I had a case where the plug and socket pins were corroded, and it gave exactly the symptoms you describe.

If the 986 has a similar connector I would check it, and even if not, I would check the diagnosis line between the immobiliser (alarm) unit and the DME.

[smartrepair]

Hi

I checked the diagnostic line wire, and it´s perfect, no corrosion,and resistance as it should be. The inmobilizer /alarm unit has a fuse and it was Ok, with clean contact points.

So, back to the original question (as it looks like the alarm unit is faulty?), could I swap the other DME/Alarm/key transponder unit to my car, althoug the other car was a tiptronic? My car is manual 1998.

[EleCTriCT]

not sure if the 534 works with the 535 system etc. to do a swap without coding you would also need the key pill and everything or else its a no start.

i think coding would solve the tip vs man but im not 100% maybe someone else knows....

A boxster with alarm issues my first check would be moisture in the carpet or floor pan - which would include popping open the alarm unit and checking for visible board damage - look for burn marks / corrosion.

[Richard Hamilton]

534 and 535 are different radio remote frequencies. If you are using a matched set, I can't see why it wouldn't work. The fuel map is different for manual/tiptronic though. Unless you get the IPAS codes with the donor set, you won't be able to get them recoded to suit your car. The alarm module is also coded differently for 986/996. You can change the settings, but again you need the IPAS codes.

[logray]

Another problem here with a 1998 year car is the DME version 5.2.2 pinouts do not match a 996 2000 version 7.2 DME pinouts.

So the DME will not fit, the harness and pinouts are totally different.

You need to keep the same DME version.

For a 996, model year 1998 through 1999 have the DME 5.2.2 which would match a 986 1998 model year (even if you've made the mods to adapt a 3.4L 996 into your Boxster).

I would keep looking for a complete set of keys, alarm, and DME if you don't want to do any reprogramming or extensive rewiring.

[smartrepair]

The combo what I was offered, has the same pin-layout (although the seller states the year is 2000) than my car. maybe the model year is 1999? So it should fit?

[smartrepair]

Richard,

Is there a BIG difference with fuel maps. If here is a minimal difference, I don´t mind...

But what worries me, is that you say the alarm module is coded differently. What do you mean exactly?

Kare

[Richard Hamilton]

I really don't know the difference in the fuel maps. There are other things in the DME program which interact with the Tiptronic module via the CAN bus which are not present on the manual.

The alarm module coding is different 996/986 due to several factors. Cabrio/coupe. No rear trunk on a 996, etc.

[Richard Hamilton]

And another thing. The Tiptronic needs to signal the DME it is in Park or Neutral to engage the starter.

[logray]

I would ask the seller for all of the part numbers. That way there is no question.

[wvicary]

Would the alarm stop the engine from cranking?

Edited April 4, 2013 by wvicary

[Richard Hamilton]

DME5.2.2 has a single connector with 88 pins. DME7.2 has 5 separate plugs with a total of 134 pins. The difference would be obvious.

The alarm might not stop the engine cranking, but if the DME can't communicate with the Tiptronic controller then it won't crank.

Kare - I would give it a miss, unless you have the ability to re-code both units, and the IPAS codes for them.