2019 Ford f150 3.5 eco boost 100k miles. I have developed a cold start rattle. It only lasts for less than 2 seconds then goes off. My auto start stop has also stopped working as well. I pull up to a stop and the symbol comes up on the dash with the slash mark through it. Checked the oil level and it was a little low, so I added some. Checked the voltage of the battery and it was 12.6 last night when I got home. Hooked up the battery to a charger and charged it overnight and the battery was 12.33 this morning with the battery charger showing fully charged. Any thoughts on what to check next?

 

Problem 1: Cam phasers need replaced

Problem 2: How old is the battery? If older than 3 years, time for replacement. You should have a dash display readout that tells you why the start stop is disabled

 

Thanks.

How urgent are the cam phasers to be replaced?

I looked through my dash display and I couldn't find a screen that said why my auto start stop is disabled. I did see a screen that said that my engine is under normal operation. I have had the truck for 3 years and haven't had to replace the battery yet.

 

I also think the battery is likely going bad. if it's a 2019, I'd bet money it is.
Rattle, cam phasers, common pos issue Ford engineered. Keep your oil changed at 4k miles, it might last a few months to a few years.

 

When you charged the battery, did you use the recommended procedure of attaching the negative lead to a secure frame ground location? This is supposed to allow the battery charge monitor to update the status of the battery.

After charging, I usually reset the battery SOC in the BCM by doing the method available and posted in YouTube. My OEM battery from 2017 lasted until just a few months ago, and I only replaced it because I had a long road trip planned.

 

No, I didn't do that. I will check that out. Thank you.

 

you can alleviate cold start rattle by flood/WOT starting auto start stop is one of the first things to quit when battery is getting tired