Hello. We have a 2015 lariat with the push button start and recently it has been acting weird. The other night my son came home and went to park the truck and shut it off but when he pushed the button the light on the button shut off but the truck kept running for about 30 seconds. The next morning he goes to start it and nothing!
I came home this afternoon and check the battery voltage and it was dead. Jump started the truck and it started right away. Let it run for a while and scanned the battery and alternator and the scan came back fine. Go the shut the truck off and same thing happens, delayed shut off. My son goes out about an hour later and the truck won’t start but everything turns on. Check battery voltage and it’s at 12.1v which is acceptable.
Has anyone else experienced this issue? I’m not sure if it’s the ignition, PCM, brake switch issue? I know it’s not the starter because the starter has nothing to do with shutting the truck off.
Thoughts?🤔

 

Is 12.1 volts acceptable?

 

My first thought is that a battery that tests 12.1 volts isn't close to acceptable; that is evidence of a battery that's nearly 50% discharged. My next thought is that letting the truck idle "for a while" did almost nothing to recharge it. I'd start by putting it on a smart charger of at least 4-5 amps overnight. The start button problem may have been a symptom of the low charge state.