Audi Repair: audi 95 A6, obd ii, audi a6

Question
Hi,
Could you help me on the question that I have on my 95 Audi A6?  The check engine light turns on if I drive for about 40min.  But everytime if I stop and start the engine again, it turns off.  So, I cannot take it to a mechanic.

Another quetion is that how I can check the engine code?
Someone told me it has to be newer than 95 to use OBD II for diagnostic.  Is this right?

Thanks for your time.
Lee

Answer
It is worth having a look, Audi was early with diagnostic ability. Since there is a check engine light there is a diagnostic plug somewhere, but it may be OBDI.  The OBD plug should be underneath the dash usually close to the lower dash panel, but I have also seen them in the center console, or sometimes hidden under a cover behind the rear ashtray, have a look in your manual to see if it is described.
Is there any action or effect associated with the engine light coming on?  Is your fuel consumption higher than usual?  Let me know,  Jan