Vag - Com Scanning: 1999 A4 1.8T

Subject: 1999 Audi A4 1.8Turbo Tiptronic

I used the "Hex-Com" adapter and located the

diagnostic port under the dash knee pad

Green means GO!

Some earlier year ~1995/1996 A 4's:

 have the diagnostic port in the console between the seats.


While this car is a 1999,

its interesting to see these covers in the back of the console

both the ashtray cover and the plug cover have a motor symbol on them.

First boot the lap top with the cable plugged in,

Plug cable into car diagnostic port.

Turn on ignition so the dash lights up like this:

 "01" - Engine:



During further measuring block readings,

I also get this error, even though the "Hex - Com" version seems pre-registered.

It happens when I try to measure individual blocks.



 "02 Auto Trans" :

Here I get the following  DTC:

00526 - Brake light Switch (f) 27-00 Implausible Signal.

WHY?  Vag- Com has this link to answer this question.

"In addition, many Automatic Transmission Control Modules will show a DTC 00526 that indicates a faulty brake light switch.   This can also be ignored and will not appear if you press the brakes once before checking for Fault Codes."

This code has come up on each of the 1999 Tiptronic Audis I've scanned.

"03 ABS - Brakes"

While the screen comes back with:

"no DTC's found"


the dash IC *** beeps and the brake warning lights flash.


 All returns to normal after I leave the "03 ABS - Brakes" screen.

WHY?  From Vag - Com FAQ page here:

"Q: Why does my dash BEEP when I access my ABS controller?
A: In many of the newer models, there will be a series of BEEPs from the dash when you access the ABS controller (and the ABS light will be ON while you are talking to it).  This perfectly normal and is done to notify the driver that the ABS is non-functional while in diagnostic mode. " 

17 - Instruments:

46 - Central Convience:

Here I get multiple DTC's but the software hides some of the DTC's.

"56 Radio" Icon:

Scanned this and the radio display illuminated and displayed "diag"


While the lap top is working the radio shows: "diag"


There can be issues with this radio,  For more info follow the link:

to Audi Fans

TOP of page

Glossary and footnotes:

DTC: Diagnostic Trouble Code?

* Off:  No key in ignition, just the door open.

** picture:  In windows 95, the drivers screen shows ports, accessories, hard drives etc..

might be under the heading of "hard ware profiles"

*** Dash IC:  IC = Instrument cluster in this example.

**** Illuminated:  The radio lights / display backlighting came on for a brief second then went out.

IMHO:  In my Humble Opinion

RPM's:  Engine rev's OR Revolutions per Minute

"Hex - Com" : Connector cable from the car diagnostic port to the computer

with Vag - Com software on it.

Vag - Com is diagnostic Software for Volkswagon and Audi.

Vag - Com is the property of and its respective owner's.

The "Hex - Com" photo is from their web page.

This page is a step by step review of my experience, with their product, I bought.

It is for informational purposes only:  I hope it helps you in your first steps / use of Vag - Com.

-Scott  TOP of page 02/09/2003