Vag com not finding ecu

**steve1976** · 02-01-2010,08:14 PM

Hi.For some reason vag com cant find my ecu. Any ideas?

**martin1810** · 02-01-2010,08:35 PM

What car and what vag-com. Lots of possible reasons.

**steve1976** · 02-01-2010,09:04 PM

Hi Martin. Its a mk3 golf gti 8v 2e digifant. 1993. vagcom 409-1 It has worked before!!

**martin1810** · 02-01-2010,11:23 PM

The fuse box should have a fuse for the obd socket. If the socket isn't live vag-com won't work. That's one place to look. Pin 16 should be 12v .

**steve1976** · 02-01-2010,11:40 PM

Thanks Martin. Will check it out in the morning. Think it is live as the led on the cable plug lights up.

**bearthebruce** · 03-01-2010,03:11 AM

ok - also check the fuse for the ECU while you are checking fuses.

Then I suggest running [Options][Test] to find the status of the K-lines. Perhaps the K-Line is shorted to ground or +12. Have you added an aftermarket radio since your last scan?

Could also be the ECU is toast - but if the car is running ok, I would not think that was the problem (and if it is running fine, the fuse is also good! dooh! Engage Brain! Remove Foot from mouth! hehe)

Can you talk with any other module in the car? I know, there are not many that talk in your car but do any others talk to VAG-COM?

**depeyre** · 03-01-2010,03:40 PM

I have the same problem on my Audi A6 1.8t 1998 (No car detection from my scanner) - Anybody any ideas which is the OMB2 fuse on mine ?

**johnwintle** · 27-01-2010,11:04 AM

Same problem on my 99 A4.
VAG-COM test OK and K line OK, no short to ground.

Cannot communicate with any controller at all, period!

Help would be appreciated. Car runs OK.

**bearthebruce** · 27-01-2010,01:27 PM

There are (2) K Lines in your 99 A4. Did both show ok?

Have you tested your setup on another car?

Are you running 409 shareware and if so, are you certain you have installed the proper drivers for you aftermarket wire?

Last, if you are certain all is installed properly, try unplugging modules to see if you can establish communications. Some modules will hang the diagnostic communications bus.

But, if it were me, I would find someone with a genuine Ross-Tech setup and have them scan my car before I started doing all this. It could be that you have a problem with your setup/wire. And no, I am saying this to hawk our product. Given no communications, you really have no idea which side of the wire is causing the problem. Running a known working setup on your car would determine whether the car has the problem or your setup has the problem. Make sense?

**johnwintle** · 27-01-2010,01:44 PM

Hi Bruce,

Genuine VAG-COM setup 908.1. System in use on a daily basis in the workshop.

This car did scan OK a while ago and I haev the full scan on another machine.
Then started to get flakey and disconnected the ABS unit and reconnected and then I could scan again. Now that does not work.

Both K lines are showing OK in the Options/Test.

So far I have unplugged and tried again with ABS, Symphony radio, alarm siren, central conveniece unit (cl pump etc) and no different.

Accessing some of the other units will require more time and effort, HVAC etc.

Any other pointers would be very much appreciated at this time.

John