997.1 can high and can lo wiring help- cant find the 2nd pair

[Stevehughesuk]

Is anyone here able to help can high and lo colours on a 997.1? I was expecting to find two pairs in the loom:

1) Black & yellow - this is there (that the first set i think)
2) yellow/white & black/white - was expecting to find this but its not there!

I have other twisted pairs:

a) black/white & brown/white
b) brown & green/orange
c) grey/yellow & red/yellow

Does anyone happen to know if one of these is the 2nd pair of can high/lows?

 

[remarklima]

Be aware there's 3 or 4 (I think) different CAN networks.

The Drive one is the main one, but there's comfort (heating AC and the like), and another one at least.

Each has their own twisted pair. I'm sure the drive CAN is yellow black, and black white. Easiest place for me was off the main ECU behind the rear seats.

 

[remarklima]

OK, found the reference.

There's the drive can, comfort, display and diagnostics.



The drive can should be:

Yellow with white stripe for the high, and black with a white stripe for low.

The gateway module under the scuttle should have all of them in. When I fitted the 3 axis accelerometer, I spent ages fishing around under the stereo / climate planels, and found CAN wiring but clearly not the drive can. I ended up hooking it up at the back of the car and connecting to the drive CAN from the ECU.

 

[Stevehughesuk]

That’s where I am totally confused, unless I’m missing it my car doesn’t have a black/white and yellow/white in the scuttle. It does have several other pairs. I’ll see if I can find near the rear shelf over the weekend.

…..it’s for a canbus immobiliser if that helps. It seems I have to use two canbus pairs for it to work.

 

[Stevehughesuk]

I’ve got a black/white and brown/white - is that possibly the drive pair on my car?

 

[remarklima]

Very odd - if you can get to the gateway unit you can check the pins, looks like 6 and 16 - assume 2 rows of PIN so they'll be next to one another. I assume it's the Drive CAN you're after to stop fuel pump / ignition coils?

On the ECU end, there's loads more room to work if you want to splice and solder connections.

The old TPC notes are here - so D connector, pins 36 and 37. That, 100% will be your drive CAN network.

What's the immobiliser? Sounds interesting...

 

[Stevehughesuk]

It’s an ampire 400 canbus immobiliser. Basically very similar to a ghost2. It needs two pairs of CAN - one for the drive to stop engine start and one for the steering wheel controls to set and input the PIN.

I’m assuming on my car the black/yellow pair are either drive or steering wheel controls, i just need to find which of the other few candidates are the second pair. I’m just totally confused why the black/white and yellow/white pair are not there.

I may pull the head unit out again and see if I can work out the steering wheel pair from there as that obviously interfaces with that. Hopefully the colours match somewhere.

 

[remarklima]

Ah, I see - it looks like the steering wheel module has both drive and comfort CANs.



Unhelpfully, you have black with a white stripe, and yellow with a white stripe for the drive can, and yellow and black for the comfort.



But if you're a very early 997 would it have the same colours as a 996 maybe? Seems strange that you do not have the matching colours? That said, if you have sold black and yellow twisted pair, that's the Comfort can by the looks of things which is good.

It's trying to find the drive CAN - I never found mine under the head unit.

Maybe the gateway under the windscreen wipers would be best as that has all three CAN buses available.

 

[Stevehughesuk]

Much appreciated, I’ll hubt anroubd under the frunk over the weekend.

I also found an epic site with all wiring diagrams on another forum if it’s helpful to anyone :

Free Service Manuals for Porsche vehicles | Operation CHARM

Detailed repair/service/workshop manuals for almost all Porsche vehicles, including electrical diagrams, recommended bolt torques, and estimated labor times.

charm.li

It seems to have pretty much every diagram for every part of every car!

 

[remarklima]

Good find! Worth a download too!

It's a PITA to get to, you need to remove the wipers, the scuttle cover and then the cover - it's tight in there! I think some have got to it under the dash as well, but worth a search!