After a deluge rainstorm yesterday the wife tells me, the E300D pops the Check Engine Light. There were no changes to the engine or driveability.

I go to Auto Zone and have them run the codes and clear the codes. Ye olde P0200 pops up. Ok, now I have since run 100 miles and no reoccurance.

Is it possible water penetrated the computer housing? I notice the harnesses going into the housing are not water tight.

I want to check the condition of the electronics inside the box, but I need to know if there are any pitfalls to doing so. Has anybody opened up the box?

Also, has anybody experienced anything similar.

The car still got 30 mpg as of yesterday and no hesitation or change in engine sounds or performance.