BOOK A DEMONSTRATION

DTC Comparison
(Why a generic OBD-II scan tool can be useless)

Posted by Andy Smith

Here’s a real-world example from my car from September 2002. My car (a 2000 GTI 1.8T) had stalled out several times over a period of a few weeks. One evening leaving work, the car stalled, but I was able to restart it. The Check Engine Light was not on, but I scanned for codes. Here’s what a generic OBD-II code reader reported:

No fault codes, according to OBD-II, everything is fine !?!?

Here’s a screen-shot from a second OBD-II program:

Same results, no fault codes of any kind !?!?

Now let’s see what VAG-COM has to say:

VAG-COM reports a total of 10 Fault Codes !!!!!

Here’s more of them:

Now using the troubleshooting sections and wiring diagrams in my Bentley CD, I tried to figure out what all of these components that are supposedly “Short to Ground” have in common..?
Without too much trouble, I found they all get their power from the fuel pump relay! To test the theory, I cleared the codes. Then yanked the relay with the engine running at idle. The car stalled instantly, and sure enough, the exact same codes reappeared. Went to the dealer and $22 later my car is running perfectly with a new fuel pump relay!

Needless to say, if the only tool I had was a generic OBD-II scanner, my car would still be stalling out intermittently!

© V-Techindia. All rights reserved.

Click Me
SUBSCRIBE TO OUR NEWSLETTER
Subscribe to our mailing list to get the latest news from our site
We hate Spam! Your privacy is Protected. Your email address will not be shared with anyone & used by only us!
SUBSCRIBE TO OUR NEWSLETTER
Subscribe to our mailing list to get the latest news from V-Tech Commercial
Your Information will never be shared with any third party.