Just an accidental discovery today, I was checking my oil level and noticed I forgot to reconnect the pressure sender to the harness - probably when I was cleaning off the top of the transmission which was another story.

Anyway, I probably ran 500 miles with it disconnected. The odd thing is I never got a oil warning light and shockingly no pending codes (all 7 monitors that my code reader recognizes) were present either. Happily I don't believe it serves no other function than to trigger the dummy light and doesn't affect driving or ECU function but shouldn't I have gotten a warning?

 

You will only get a warning for the check engine light for emission related problems. As far as the oil light it wont come on unless the circuit is complete. Thats the job of the sending unit is to complete the circuit when the pressure is too low. When its disconnected its always an open circuit, so it light up.

 

That's the odd thing, my oil light didn't light up, it's only lit when the key is in prior to ignition starting the engine but so are the rest of the lights.