Dumb question about "Check Engine" light.

Not so dumb... and the answer is "yes" to the first question and "no" to the second. The ECU has learned a lot about how your engine expects to run and will complain with a "check engine" light over things more trivial than the disconnection of sensors. Eventually it gets tired of whining - that is, it learns how to operate the engine again - and turns off the light. The interval is typically specified as a certain number of warm-up intervals, but may include specs for number of times the engine is started and the number of minutes elapsed.

I had to have my '93 Chevy work truck tuned up in a distant town, and it lit the "check engine" light the rest of the day.

Mike

One of the sensors was not initially reconnected properly. When you double checked everything you must have reseated the connector. In this case, the computer will turn off the light after 3 complete system checks, each of which takes about 30 minutes of mixed driving. If you're really curious about what the problem was, the code will be still stored in the computer for quite a while before it's automatically erased. If you're not curious, or it's inconvenient to get the code read, then you can safely ignore this.

Thanks to the Mikes for the quick answers.