'91 90 check engine light comes on over 65mph

Any one have an idea why after we got our daughter's 1991 Audi 90 back from a repair shop that the check engine light comes on and stays on when the car is
driven over 65 mph? Otherwise car runs fine. Thanks. Rod Michaelson Walnut Creek, CA '03 A4 avant quattro sport '95 90 quattro sport '91 90 cs
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Rod, Is there any way to pull the codes and find out what is tripping the check - engine over-rev, knocking, temperature sensor, etc.? What was done at the repair shop - look in the area of the work for loose/broken/unconnected sensor wires. Cheers! Steve Sears 1987 Audi 5kTQ 1980 Audi 5k 1962 and '64 Auto Union DKW Junior deLuxes (SPAM Blocker NOTE: Remove SHOES to reply)

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I have a 93 Audi 90 and you can dump the codes using an odd but effective procedure. I found it out at 12v.org, but that site isn't up any more. It involves shorting the computer terminals in the fuse box and watching the check engine light flash.
The most common CE code is 2411, EGR valve. It comes on if the car warms up but the EGR bypass hasn't. Mine comes on on really cold days.
I'll keep an eye out for the procedure.
Steve
1993 Audi 90

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http://www.carsoft.ru/avtorepair/vwfault.html
the connectors are in the fuse box, not where they indicate.
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Thanks for the great input, Stephen!
Rod
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