I'll check the lower harness first. It probably needs to be replaced anyway. That would save me the cost of an oil pan gasket and sensor if it fixes the problem. Maybe I disturbed the lower harness when I changed the motor mounts a few weeks ago.

__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles