I washed the engine yesterday afternoon with a garden hose (light pressure spray patern) and the check engine light came on this morning. The engine was running rough for a bit and then turned back to smooth running condition after about 5 miles of driving, however, the check engine light is still on now. Did I screw something up? Will the light reset itself after a few starts or do I need to go to a dealer/repair shop for this?

TIA gor any advises.

Garry
1997 E420 w/75K miles