harryb

Well, I finally got my hands on a PST2 to play around with. I've had some problems though. The computer is reading all of the control modules fine....except for the DME. On the DME, it says...."System not found".

I've tried it with the car idling, and with the car in the on position but not started.

So far, i've got a couple of opinions. Some say it is because my '96 has had a DME swap with a '97 and also has been remapped for my Garrett hybrid turbos.

Others say it may be a cable problem, but it's hard for me to believe that in light of the fact that the computer is reading the ABS module, Alarm module, Air Conditioning module just fine.

Any help would be gratefully appreciated since I spent big bucks to get this computer.

Regards to all for a great holiday season,
Harry
harry@brandtmd.com

Lorenfb

"Some say it is because my '96 has had a DME swap with a '97 and also has been remapped for my Garrett hybrid turbos."

That's the most likely problem. There were some earlier versions of the PST2 software
(<#24) that had problems. If the immobilizer was bypassed for running/starting, it
may still have to be reset via the key unit.

harryb

Thanks Loren!!

I have version 24 of the software. Can you explain what the "key unit" is?

Harry

harryb

Well, now i've tried just about everything....and I can't get the PST to pick up the DME

Any other suggestions?

sonny1

Try it in another car,see if it works,Sonny.

grmnxtc

Hey there...

Just chiming in.

On the later 95 production, the square OBD II connector had two "k" wiring circuits (I know, mine does).

IIRC the DME and Tiptronic are on one circuit, the ABS, Alarm, airbag and climate are on the other,

Do you have a tip or manual box? Manual would obviously not have a controller, and *IF* your car has a late 95 wiring loom, then you need to switch over pins 7 and 3 (which are the two K lead circuits).

First though, I'd check the pins fitted in the connector and if 7 and 3 are fitted, that might be the issue....

I made up a custom OBD lead to switch over the two K circuits to check out each subset.

Just a shot in the dark.

harryb

I'm pretty sure you are right about this. I've heard from another person who described the same thing. And a Porsche mechanic at a dealership had some difficulty at first getting the computer to read my car...but ultimately was able to, presumably by switching to a different cable or switching something in the software. He was using the new PST3 (or PIWAS).

I've checked the wiring diagrams and you are correct that there are two K circuits on my car. And I do have a manual.

Could you please describe how to contruct the custom OBD connector. I am relatively new to this. Do I need to reverse pins 3 and 7.....or do 3 and 7 need to be tied together?

Thanks a lot for the help.

Harry

grmnxtc

Harry,

Got the PM, but thought I'd answer here as it might help others when it's old and in the archive.

I bought an OBD2 extension cable from these folks: (cable 3)

http://www.multiplex-engineering.com/cables.htm

And then chopped into the middle, used a multimeter to find pins 3 and 7 ( IIRC it was the brown and yellow wires), then crossed them over and used it to get my cirucit up and running.

I'm not sure why 7 and 3 are not connected... there's probably a good reason why Porsche did NOT connect them... but who knows...

I thought it was best to risk a $40 cable than a rather more expensive set of Porsche control units and leave the car "stock" for the times when a dealer needs to look at the units.

It worked for me. Hope it works for you too.

I'm actually going to make another cable set for the "switched" wiring to my Hammer just so I have both cable types available.

Clive.

harryb

Clive:

Thanks for the help, but I'm still struggling with this. I have the Bosch accessory box (part # 1684462346) and the a cable with an OBD connector on one end and 6 colored leads on the other, so I can basically move around the pins to try different possibilities.

Currently I have the Red pin in 16 and the Yellow in 15 (which I know are correct!!).

I have two black pins in 4 and 5 (which I know are correct!!).

When I put the the Green pin in 3...the PST2 reads the ABS, Alarm, Heat/AC modules....but not the DME

When I put the Green pin in 7...I was expecting to be able to read the DME....but no luck...still says "System not found".

I even jumped pin 3 AND 7 and it still would not read the DME.

I've tried just about everything but still can't seem to get the PST2 and the DME talking to each other

Any other suggestions would be most appreciated.

Thanks.

Harry

grmnxtc

crap... just typed this all out and hit the wrong key.... here goes again...

Just a thought, you mention "swapping and re-mapping". Is there a chance that the "re-mapping" has killed the operation of the OBD circuitry? Any way to check the operation via the person who sold it to you/did the swap?

Another thought. Do you have a "friendly" dealer who can plug in their tester and see what happens (if it sees the DME or not). That would answer a lot of issues perhaps...

I'm afraid I have a Hammer with 8.1 of the Porsche software, and not a PST, so I'm only able to offer sideline help here... Just some random thoughts you might be able to try.

Sorry, I'd love to be able to point and say "Aha! theres the issue" but sadly I'm not.

Regards,

Lorenfb

OBDII uses pin 7 (K-Line bidirectional) and pin 15 (L-Line). The PST2 uses a multiplexer
to select the appropriate pin for each ECU, e.g. DME, ABS, or SRS. As mentioned, pin 3
(not an OBDII pin) selects the other ECUs (not the DME). You should not have to be
reversing pins.

The only problem I've had is when the immobilizer has not been reset (still in "armed" mode).
If the immobilizer still prevents starting, then you'll know if it's inhibiting the communications.
If the immobilizer has been disabled in the DME, i.e. via a mod, it still maybe causing
a communications problem with a scanner.

The other possibility, as I mentioned before, is that the OBDII firmware has a problem
the result of the DME mod. Too bad you couldn't have tested the DME before the mod.

Bottomline: Find another DME to use to determine where the problem is.

harryb

Loren:

Thanks. You know your electronics. I think you figured it out!! The problem is that the car will turn on with or without the immobilizer now since I had the DME modified and jumped the starter relay. So I may be performing the diagnostics with the car "immobilized" but turned on. Of course, this could never happen in the normal circumstance since the immobilizer will not allow the car to turn on!! Sometimes while I am driving the immobilizer light is on continuously, and other times it flashes. I have determined that this is based on whether I happen to have hit the immobilizer button on the remote or not. Unfortunately, I haven't tried diagnositics both ways yet, because until you mentioned it, I hadn't thought of this.

The guys at Protomotive just called a few minutes ago and they had a similar thought. I'm going to send them the DME and they are going to reprogram it so it will work with diagnostics at all times.

The diagnositics are one thing...but I actually forced a fault by disconnecting the MAF sensor and starting the car. This didn't trip the check engine light!! My concern is that faults in the DME are not being picked up which could create serious problems.

I think I'm on the way to finally getting this worked out.

Thanks to all (Frank, Clive, Loren) who have been so tremendously helpful.

Harry

harryb

OK guys...now that I'm finally communicating with the DME.....on to the next issue:

When the PTS2 polls the DME it now shows a ? next to DME and says "Diagnosis Software Unknown".

It will read faults now.

Under identification is says:

Diagnosis software number
000

Porsche part number:
99361861100

What can I do about this??

Thanks again for all the help.

grmnxtc

Progress... such a relief I'm sure (and Frank knows how You and I feel )

Sounds to me like another trip back to the re-programmers....

The DME should report software version M04 (I think?). Not 000.

That's probably a modification done by the Protomotive folks. If the PST doesn't see the version it's expecting, then I guess it barfs in the way you mention.

Lorenfb

As I've said many times on this forum, modifying the DME unit in late model vehicles,
i.e OBDII ones, causes nothing but problems in the long run with little to no performance
improvements.