Picked up a very nice 1997 E300D this summer which was religiously factory maintained, by the prior (and only owner) with 173,000 miles on it.

The only issue is the Check Engine, Engine Electronics lamp comes on during start up and during shut down.

Since the car was free, I took it, all I do is hit the reset button to shut off this reminder.
I drive this car as my daily driver, it starts and drives smooth, no hesitation, now has 177,000 miles on it.

Replaced the ]alternator two months ago.
Now with the onset of winter here in Houston, when the outside temperatures have dropped down below 60F the Check Engine, Engine Electronics lamp does not come on during start-up or shut-down.

Temperature went up above 70F (estimate), engine operating temperatures went back to normal, Check Engine, Check Electronics lamp lights up again during start-up and shut-down.
Now for the past week, the outside temps have been low again, and the Check Engine, Check Electronics lamp does not light up again.

I had the codes pulled before I took it and the following codes showed P0120, P0200, P380, and P0600.

I suspect with this issue being related to temperature, it might be the P0600; K-40 relay.....

any ideas?

I would guess a circuit board issue in the K-40 relay.

.

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