Replace the Key Fob Battery

Reviewed by the Service Reset editor · Updated September 27, 2026 · How we verify

These instructions apply to the RAM 1500 Mk5 (DT) 2019-present.
For other models, please choose your vehicle here.

A weak coin cell is the usual reason a RAM 1500 (DT, 2019 onward) smart key loses range or throws a “Key Fob Not Detected” message. The battery swaps in a couple of minutes. Most 2019-onward smart fobs take a CR2450 3V cell; some remotes use a CR2032 — match whatever you remove.

RAM 1500 DT proximity smart key next to a Duracell CR2450 coin cell
A 2019-onward RAM 1500 smart key alongside its CR2450 coin cell. Illustrative frame.
RAM 1500 smart key opened at the battery bay with the CR2450 coin cell lifted out
The fob opened at the battery bay, CR2450 lifted out. Illustrative frame.
  1. Push and hold the small release button on the right side of the fob and pull the emergency key out with your other hand; set it aside.
  2. Hold the fob button-side down. Find the small rectangular gap on the left edge between the housing and the back cover and gently pry it open with a small flat screwdriver until it snaps.
  3. Find the matching gap on the right edge (it sits a little further toward the corner), pry it open and lift off the back cover.
  4. Slide the old battery downward and back toward the key ring with your thumb to release it from under the retaining lip.
  5. Fit the new CR2450 with the + side facing up, sliding it under the small lip on the top edge of the opening. Handle it by the edge — skin oils shorten battery life.
  6. Line up the top edge of the back cover with the top of the fob and press the edges into the hinges until every edge snaps home with no gaps.
  7. Reinsert the emergency key until it locks into place, and test lock/unlock.

Frequently asked questions

CR2450 or CR2032 — which one?

Most DT proximity smart keys use a CR2450 (3V). A few remotes use a CR2032. The safe rule is to fit the same type you take out, + side up.

Do I need to reprogram the fob afterwards?

No. Changing the battery does not erase the fob — it keeps its programming. (New, blank fobs do need dealer programming.)

The fob is dead and the truck won’t detect it — how do I start?

Hold the fob flat against the ENGINE START/STOP button and press: a backup antenna reads the transponder so you can start and drive home, then change the battery.

If a battery or charging warning appears after the swap, check the stored codes on autodtcs.com before assuming a fault.

Independent guide — not affiliated with RAM. Always follow your official service manual and safety precautions. Read our full disclaimer.

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