Re: Reading Fault Codes

["Scott Mo." <scottmo@teleport.com>]

>SSpangenbe@aol.com wrote:
 >I can't get my light to blink any codes!  Any suggestions on what I'm
>doing wrong?

One thing you can check, is to verify the fuse supplying +12V to the
fault code "Black" connector is ok. With the ignition on, the left
diagnostic connector "Black" upper connection should have +12V, the
lower connection pin should be ground. Fuse 21 on the 3B and dual knock
MC engines supplies +12V to this diagnostic connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> I'm using a low voltage tester, which is 2 alligator clips connected to a small bulb, that I picked up at Kragen.  I shorted out the 2 terminals before connecting the tester per the diagram but no blinking lights at all.  
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I assume you are shorting out the correct terminals for at least 4
seconds? I don't know the wattage of the test light bulb you are using,
but the dash light bulbs are only 1.2 Watts, I don't know the melt down
rating of the transistor inside the ECU supplying ground for this fault
code light but what is a few hundred milliamps between friends....

If your dash mounted 'Check Engine" light bulb is installed, you can use
the Check Engine light bulb instead low wattage light bulb connected
across the fault code connectors. or as mentioned the LED light of
course can be used with the appropriate resistor to limit the current. 
All of this stuff "should" be explained in gory detail at my web site at 

http://www.teleport.com/~scottmo/ecuf.html

if it ain't clear and understandable, let me know.....
> 
> I drove my 89 200T and got it warmed up as suggested, did not turn it >off before beginning the test.  I even tried the fuse in the top of the >fuel relay, just in case that would help.

In some cases with the correct fuel pump relay with the contacts in the
fuse holder, this "fuse" insertion technique will work even with the
1989-90 200T/Q cars equipped with the three colored fault code
connectors under the dash.
> 
> How expensive is the factory scan tool, VAG 1551 or VAG 1552?

The VAG1551 is the larger unit, about the size of a toaster oven, it can
be purchased for ~$4500-5000 and it has the built in printer function,
there may be some used versions floating around, but you need to get
the  latest software/firmware for this tool.  

The VAG1552 is the smaller/compact unit which opens like a clam shell
with a small LCD screen, and buttons etc,  it is about 8 X5 X 2 inches
big and can be purchased for ~$1500, don't ask me how I know.....the
nice thing about these VAG1551/2 tools, is you can access fault code
information on the later Audi/VW's for the ABS system, transmission, air
bag systems, traction control, seat memory, sunroof, intrusion/alarm
system, yada yada yada etc, which makes trouble-shooting a little more
straight forward....

With the VAG 1551/2 you can also look at the learned, i.e. adaptive
values stored in the ECU memory for the idle stabilizer, O2 sensor
(lambda)etc. to understand what range the ECU has been adjusting itself
to and locate problems when it goes outside the recommended range.

CarComp in the US, makes the PC/laptop based VAG 1551/2 software
emulation tool for the VW/Audi diagnostics with the appropriate fault
code connectors and PC RS-232 serial cable interface. This is supposed
to do all the stuff the VAG1551/2 does and more, and sells for $495 and
can be used with any 486 or better PC/laptop.

I have one of these CarComp software/hardware packages that I never used
and really don't need anymore now that I have the VAG1552 tool...

Contact me if you are interested in purchasing it...and would like to
move up the food chain of VW/Audi Diagnostics...Details on this
software/hardware package can be found at...

http://www.carcomp.com/ 

HTH
-- 
Scott Mo.
1989 200TQ
1988 5000TQ
1966 VW Beetle
http://www.teleport.com/~scottmo