I get that problem every year when it gets really cold here (below 32F is really cold for Tucson). It is only intermittent and happens less than a hand full of times per year on start-up.

Like yours, it corrects itself after shutting down and restarting. My ETA has been rebuilt by 4Mercedes and I doubt it is bad. The wiring harness has also been replaced. It seems to happen more often when it has been cold and wet. It's a mystery. If you figure it out, let us know.

By the way, if you do a search for Mercedes ETA on Youtube, you will see a video that shows you how to test the ETA yourself with a digital voltmeter.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles