My 93 Cabrio has the 16 pin OBD-1 plug, with the red LED and push button. I also fabbed a blink light box per widely published info.

I'va had car for several months, no CEL. While swapping fan clutch I decided it would be a good idea to unplug the air pump, to prevent the pump from running and ruining; I live in a non-test area.

A few days later CEL came on.

On pin 3 I get codes 4 , 9, 18, 23, 26
On pin 6 I get codes 3, 8
On pin 7 I get code 3
On pin 8 I get code 1 (mericiful Mercedes gods, thank you!)

Is there a way to clear all these codes and start fresh, I am hard pressed to see how they would all be related the air pump. Or how a bunch of old codes would all "wake up" at once from the cobwebs of the ECU memory.

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91 300 TE 235K
93 Cabriolet 155K sold
92 300 TE 200K boneyard