ECU code reading and aftermarket radio

[diaftia]

Does installing an aftermarket radio have the ability to interfere with reading CEL codes from the ECU? After I installed my AVIC-F90BT I got a CEL and I cannot pull the code from the ECU. As a matter of fact I think I fried my el-cheapo cable from ebay and my neighbors SNAP-ON code reader wont even connect.

I even disconnected the radio and reconnected the original to see if that would do anything and I still got nothing.

Anybody seen this before?

[diaftia]

Nobody has seen this before? Maybe its not related to the radio install but it seems like a strong coincidence. Granted I did put the original radio back in and got nothing. I have a ross-tech coming so hopefully that will be able to read it.

[diaftia]

Found this... gonna see what I can do.

http://www.ross-tech.com/vag-com/aftermarket-radio.html

[2BblkAudis]

I used to work for a VW dealership and have seen some of the service tech say that they will not scan the car if an aftermarket radio is in there. They said something about how it can fry the VAG reader that the dealerships use. Not sure of the validity or if it's a myth but I have heard about some interference.

[diaftia]

I used to work for a VW dealership and have seen some of the service tech say that they will not scan the car if an aftermarket radio is in there. They said something about how it can fry the VAG reader that the dealerships use. Not sure of the validity or if it's a myth but I have heard about some interference.

Yep, its possible. Check this out from the ross-tech article:

The Problem

Nothing in the car cares if the K-line is shorted to +12. The K-Line is not used for intra-vehicle communications. But a scan-tool initializes a communications session by pulling the K-line to ground. The K-line is supposed to have some voltage on it, but through a high-impedance source. If the K-line has "hard" +12 on it, something has to give! What "gives" is usually the scan-tool's output driver for the K-line. And fixing a VAG-1551/1552 with a blown K-line driver is expen$ive! But the ISO-COM PC<->Car interface adapter that we provide with our VAG-COM software has a small user-replaceable fuse protecting the K-Line output driver, and there's a spare fuse taped under the lid of the little box. No big worries there..:-) Our other interfaces use output drivers that are thermally protected against shorts. They don't need a fuse. If you plug them into a car with the K-line shorted to +12, they simply won't work in that car, but it won't hurt them either.

The Dealers

Some dealers will refuse to scan any car that has an aftermarket radio. Since most dealers have "killed" a few of their very expensive scan-tools, I can sort of understand why. The best solution: Buy our VAG-COM software and scan it yourself..:-) If you can successfully scan the car with VAG-COM, you know it's safe -- and can likely convince the dealership that it's safe too.