Do your back-up lights work...climate control? The CEL is on the same fuse. When the fuse fails the CEL is activated. At least on a federal '90.

Codes are real time only, unless you are in california. This is why you need to provide you LOCATION.

CA cars are different.

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'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E