Variomatic Ground Trigger Wire Testing

[Gary D]

I suspect I have a faulty actuator on a '98 986. I norder to prove it I want to check the ground trigger (earth) to pin 52, but I don't know which of the harness plugs it's in.....?

[Loren]

:welcome:

You need a special tool (break-out box) to test connections coming out of the DME - to avoid damaging the DME.

What fault coed(s) are you getting?

[Gary D]

Thanks for reply Loren. I'd been to have another look, & came away puzzled by 'pin52' as none of the connectors go up that far. So is pin 52 on a DME strip?

Fault code I've got is P1531. The solenoid works, & is getting 12V when the ignition is on. Someone sent me the the diagnostic procedure, hence I was trying the next step...... :huh: So I presume a break-out box 'exposes' the DME connections?

cheers

Gary

[Loren]

Correct.. And the special break-out box for a DME 5.2.2 (MY1997-2000) is different from the DME 7.2 (MY2001-2005).

I can't find a photo but here is a diagram of the interface. A few have made their own but it is a lot of delicate work.

(click to enlarge)

[JFP in PA]

Correct.. And the special break-out box for a DME 5.2.2 (MY1997-2000) is different from the DME 7.2 (MY2001-2005).

I can't find a photo but here is a diagram of the interface. A few have made their own but it is a lot of delicate work.

(click to enlarge)

break-out box.png

The tool (special tool 9616) is a Porsche "Pin out" or "DME break out" box for testing circuits. Porsche's Black Forrest version is about $2K (if you can find one), OTC makes something similar, but equally rare, called the OTC 3226:

This allows you to plug into the DME's wiring harness and test individual circuits electrical properties to make sure they are functional. All in, sells for about $1k.

[Loren]

JFP - I am not sure they make one for the old DME 5.2.2 with the round connector.

[JFP in PA]

JFP - I am not sure they make one for the old DME 5.2.2 with the round connector.

I think they did at one time, but I have no idea what they are doing now, as they seem to have dropped a lot of the little used adaptors. Along with the correct DME connector adaptors, you would also need the pin overlay maps to match, which are even harder to find unless you happen to come across someone with one already set up for Porsche. Every once in a while, one will show up on flea bay or at car show sale, but even these are few and far between. That said, I have never seen a 9616 come up for sale.

[Gary D]

Thanks for the info guys.......no way I'm going to try to acquire one. When I get this fixed (when......... ) the car will be up for sale as I've bought an old 911.

It's most likely I have an actuator fault, but I need to try to rule it out. Does Porsche specify the ground wire test because the DME can go faulty, or is it a 'faulty wire' type fault.

I don't really understand how the system works, is it the DME just making a connection to ground & where is the ground point it goes to? In the trunk or a distance away?

I understand that sometimes the DME 12V supply goes faulty, has anyone heard that the ground-switching does?

[JFP in PA]

When using one of these pin out boxes, you are isolating the entire wire loom and sensors or controllers where they connect to the DME, so you can test the entire circuits that the DME would be seeing. In this way, if the circuits are OK, then the DME is suspect. Usually, it is one of the sensors or the wiring that comes up as the problem. It would, however, be very difficult to replicate what these devices do by testing individual wires and circuits.

Porsche usually grounded the DME close to where it is mounted, the exact location varied with year and model somewhat do to space limitations.

[txhokie4life]

On 10/7/2013 at 12:10 PM, JFP in PA said:

The tool (special tool 9616) is a Porsche "Pin out" or "DME break out" box for testing circuits. Porsche's Black Forrest version is about $2K (if you can find one), OTC makes something similar, but equally rare, called the OTC 3226:

This allows you to plug into the DME's wiring harness and test individual circuits electrical properties to make sure they are functional. All in, sells for about $1k.

 

 

Any idea what the 88 pin adapter for the OTC is?  I can find the basic box on eBay easy enough,

 

thanks,

Mike

 

[JFP in PA]

27 minutes ago, txhokie4life said:

 

 

Any idea what the 88 pin adapter for the OTC is?  I can find the basic box on eBay easy enough,

 

thanks,

Mike

 

 

Hi Mike-

 

I have never seen a late model Porsche adaptor for the OTC pin out box, the 80 pin version for the early cars exists, but that won't work on the later cars.  There may not have been enough demand for them to create one.  Sorry...……...