Tactics

Is there a way to verify that your CEL hasn't been tampered with? Perhaps there is something I can do fairly easy that WILL throw a CEL.
But won't harm the car.

I've had sensors that are dead(for sure) and no CEL. I also can't pull any codes from my ECU via the CEL. (Have to use a scan tool)

I suspect the previous owner might have crossed the wires to the oil lamp light or something. Just a hunch...

Thanks
Tac