my ECU communication port has the wrong wires

[wemorgan]

An off-topic mixed with electrical question here, you decide:

My Audi A2 had cruise control fitted today. The final stage was to program the ECU to tell it of the CC feature. The laptop failed to 'see' the car. When plugged in to another A2 all was fine. So on closer inspection it was clear that the vag-com port had different colour and different numbers of wires as in the circuit diagram. The colour wires that were meant to be there were nowhere to be seen.

How can the wires be so wrong? How will it be possible to fix this?

Thanks for any help.

 

[scumbag]

How will it be possible to fix this?

Thanks for any help.

Buy a Mercedes. end of problems. see simple.

 

[wemorgan]

That's true. Changing from a W208 CLK with rust to an aluminium A2 I was eliminating one problem, but to be replaced with another.

 

[scumbag]

That's true. Changing from a W208 CLK with rust to an aluminium A2 I was eliminating one problem, but to be replaced with another.

rust is easy to fix...bit of sand paper, elbow grease, daub some paint on, job done.

leccy issues......different ball park. You need to throw them away and start again.

 

[GrahamC230K]

This Ross-Tech documentation http://www.ross-tech.net/VCDS/download/VCDSCompatibilityCharts.pdf would suggest VCDS (previously known as vag-com) is compatible.

Try reading up further on the Ross-tech site of maybe a A2 forum - I know there is a big following!

Was it a case of adding the stalk or were any extra cables run to the ECU?

 

[wemorgan]

This Ross-Tech documentation http://www.ross-tech.net/VCDS/download/VCDSCompatibilityCharts.pdf would suggest VCDS (previously known as vag-com) is compatible.

Try reading up further on the Ross-tech site of maybe a A2 forum - I know there is a big following!

Was it a case of adding the stalk or were any extra cables run to the ECU?

Thanks for the link.

I've posted the same question in the A2 forum, but it's not as well frequent as this site

An additional wire was routed to the ECU. The CC was eventually fixed by plugging the ECU in to another A2, reprogrammed, then plugged back in to my car. But for servicing and general fault diagnostics I'd really like to get the vag-com working.

 

[wemorgan]

Just a follow up incase this happens to anyone else on another car.

It seems that my 2004 car has the wires of a 2001 car! It begs the question how this can be. I'll be doing some further hunting around.

 

[wemorgan]

Latest update:

I returned my car to the garage today, for them to investigate why I get no signal to the vag-com.

The conclusion was that there is a fault with the stereo. When they disconnected it, the vag-com port work OK. It doesn't explain why the wiring is from a MY 2001. But since it works, I'm not too bothered.

The technician said that it looked like liquid had spilt over the stereo and moisture gathered on the CAN BUS. With the cup holders above the stereo this seems plausible.

It does seem odd though that despite this fault the stereo continues to works.

So, my next task is to find a second hand Audi Concert stereo.

A thumbs up to the garage.
A thumbs down to Audi for putting cupholders over a stereo.

 

[lynall]

Obviously a decent mechanic as rare as rocking horse poo.



Lynall

 

[wemorgan]

Ah, I forgot to update this thread. Information from the A2 owners club suggests that the above fix was a fudge!

The reason why your port will work when the radio is disconnected is that it is the hub (along with the clocks) of the CAN bus system and when it is unplugged, the CAN system (which over-rides the K-line diagnostics at your port) is disabled, as the A2 only really uses CAN for infotainment.

I wont pretend that I fully understand the above, but it seems my problems are not quite over. Though at least I know now when I want to read the diagnostics I need to unplug the stereo.