I have a 2000 MBZ c230 that has again failed the functional part of the smog test. I was not suprised as I have known about this issue as long as I have owned the car. Everytime I have to smog the car, I have to go to a regular smog check place, fail the test, then set an appointment with a referee center and they pass the car. No one seems to have any idea as to why the car will not talk to the 1st smog check machine, which causes the test to fail.

I heard offhand that the gd radio's in these cars can cause a failed smog test. Can anyone confirm if this is true? I know that MBZ makes it very difficult to change out the radio in many of their cars with an aftermarket radio, but having the radio actually be required to pass a smog test is about the worst case of vendor lock in I have ever heard. This car has the original radio, I have never changed anything with it, maybe someone else did. The amount of effort, money and time all this bs people have to go through for this is unbelievable. In fact I would say all the trips I have made to the referee center over the years have offset any saved gas or pollution.

Everytime when I get the first smog test done, I ask the tech how the numbers came out - the car always does very well in the test results, scoring very low levels of pollution. Looking at the test results all of my measured test results are far below the average measured values. I would like to find out what has caused all this wasted time over the years, I hope it was not the gd radio or some form of Mercedes vendor lock in.

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1996 E320
2000 C230 Kompressor
1988 190e 2.3 - 225K miles, owned for 7 years. I cannot say enough good things about this car. Very well built, even at 225 it ran like new.