The first thing you need to do is check your oil if your Jeep hot oil warning is on and won’t start. If your Wrangler has an automatic transmission, it’s also a good idea to have the transmission fluid checked. Either or both of these fluid levels being low can cause the light to come on and prevent your Jeep from starting.
If your oil and transmission fluid are optimal, your next step is to check the battery. JK series Wranglers exhibit some funky behaviors when the battery gets low. Check the charge level, inspect the terminals, make sure it’s grounded properly, and look for corrosion. It’s a good idea to make sure your fuses and relays are good.
In the vast majority of cases, this will be a fluid level problem or a battery problem. But in rare instances it might be related to a faulty oil pressure sensor, a bad starter relay, or issues with the starter itself. You’ll need a mechanic to investigate these issues further if that’s the case.