How to “talk” to your VW Golf or Jetta.
What year is my car, and why does it matter?
The MKIII model line was spread over several years, over the years the technology unused to communicate with the vehicles ECM and hardware changed. To find what “year” your car is the easiest way is to open the hood and look at the emissions decal. There it should say something like “this vehicle meets or exceeds all federal motor vehicle safety standards for the 19XX model year.
Another way is to punch your VIN into the VIN tool and see what year your car is.
The 10th digit = the year the car was made.
For example - 3VWCB0530PK002640 = “P” = 1993
1993(P), 1994(R), 1995(S), 1996(T), 1997(V), 1998(W), 1999(X)
In general the MKIII model line went like this (for US cars only!)
1992-1995 = OBDI
1996-1999.5 = OBDII
OBD = On Board Diagnostics.
OBDI = A VW only system (engine, abs, and air bags)
OBDII = A VW system with (engine, abs, air bags, and starting in 1998 the radio and CD changer) AND universal scan tool interface.
Any OBDII code reader can be used to read engine codes and only engine codes.
For more info on all the details of OBDII - visit http://www.obdii.com/background.html
Interface for 1992-1993 MKIIIs = Behind button blanks
(where the A/C switch is) - This is known as a 2x2 system.
OBD I Interface for 1994-1995 MKIIIs = Above the cigar lighter, next to the ashtray. Pull off the blank panel to reveal the ECM interface. The connector is colored BLACK
OBD II Interface for 1996-1999.5 MKIIIs = Above the cigar lighter, next to the ashtray. Pull off the blank panel to reveal the ECM interface. The connector is colored PINK.
Note! Some of the EARLY 1996 Model Year Cars have a BLACK OBDII connector.
OBDII Production started in late 1995 (8/95 - 9/95).
What is this factory tool I hear about called a VAG 1551?
It is the factory (now very defunct) scan tool.
Great, I know what year car I have, and how to get to the connector. How can I read codes?
Option 1 - The factory scan tool called a VAG 1551. It is the factory (now very defunct) scan tool - This works for OBDI and OBDII cars.
Option 2 - This ONLY works with OBD I cars! OBDII cars cannot blink codes!
Use the blink out code method. (free!) Follow the directions closely!
Option 3 (Best option) - Use a program called VAG.COM - Works with OBDI and OBDII cars. Use a laptop!
NOTE: OBDI 2x2 adapter cars must buy a 2x2 adapter cable!
You can buy VAG.COM software and cables from
*I* Use an E-bay serial cable (search E-bay for VAG.COM), and then download the shareware version of VAG.COM.. “ Release 311.2 Posted 16. November 2003 For ISO-COM and most Third-Party interfaces“ - Found in the Ross-Tech download archives page.
Option 4 - OBDII Cars Only!
Get a generic OBDII scan tool of your car. Many are on the market for under $100. Most auto shops may also scan your car for free. You can only access engine data. No ABS or Airbag code data is available with a generic OBDII scan tool.
What do the codes mean?
Here are some code lists.
OBDI Codes - http://www.bentleypublishers.com/tech/vw/vw.dtc.table.htm
OBDII Codes - http://www.obd-codes.com/trouble_codes/volkswagen/ and http://www.bentleypublishers.com/tech/vw/vw.dtc.table.htm
If I clear the code.. does that fix the problem?
No, it will come back.. Codes are set from an error in the ECU that is detected with the vehicles hardware (sensor, wires, etc..) you must follow a diagnostic test in order to find out WHY the code was set. Never ever "just erase" a code in order to "fix" a problem.