These instructions apply to the Ford F-150 Mk13 (P552) 2015-2020.
For other models, please choose your vehicle here.
If the key-fob battery in your 2015–2020 Ford F-150 (P552) goes flat, the truck can’t detect the fob to start normally. Every Intelligent Access F-150 has a backup slot that reads the fob directly, so you can still start it and drive without a new battery. This is the US-market procedure.
- Unlock the door first: slide the release on the back of the fob, pull out the emergency key blade, and use it in the driver’s door lock.
- Get in and press the brake pedal and hold it.
- Find the backup transponder slot — on the 2015–2020 F-150 it’s in the bottom of the front cup holder in the center console (lift the rubber liner).
- Drop the key fob into that slot, buttons facing up.
- With the brake still pressed, press the START/STOP button. The truck reads the fob’s transponder and starts.
- Replace the fob battery (a CR2450) soon — the backup slot is a get-you-home method, not a fix.
FAQ
Where exactly is the backup slot?
Bottom of the front cup holder in the center console on most 2015–2020 trucks; a few trims put it in the console bin. If it isn’t in the cup holder, check the “passive anti-theft” page of your owner’s manual.
Which battery does the fob use?
The 2015–2020 F-150 Intelligent Access fob takes a CR2450 coin cell.
I pressed START and nothing happened.
Make sure the brake is firmly pressed and the fob is actually seated in the slot. If the dash is dead too, your truck’s 12 V battery may be flat — that’s a different problem (jump-start needed).
How do I lock it again afterwards?
Use the emergency key blade in the driver’s door; the other doors follow.
If a “key not detected” or immobiliser code appears afterward, look it up on autodtcs.com.
Independent guide — not affiliated with Ford. Always follow your official service manual and safety precautions. Read our full disclaimer.