Today, I was in a rental vehicle (Tucson, fairly new model) and noticed this which I hadn't in any vehicles before:
Inserting the key and turning it (without starting the engine, but just before) makes all the lights in the dash appear and then go away except check-engine light, battery light and engine oil light.
I was under the impression that if any light persists, then that service is needed. However, these 3 persistent lights disappear once the engine starts. I am confused as to why just these three lights persisted just before ignition.

2 Answers 2


The engine oil stayed on because it indicates low oil pressure, theres no oil pressure until the engine is running.

The battery light stayed on because it indicates the alternator isn't charging. It doesn't charge until the engine is running.

The check engine light stays on until the engine is running. It turns off when the engine is running with no faults.

90% of cars do exactly this.


As stated by @Terry Gould, most cars do this. All the lights turning on is a bulb-check feature, or at least, that's what I've been using it for :) The lights that stay on is explained by Terry.

You should only worry about lights that stay on while the engine is running.

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