Start the Car With a Dead Key Fob Battery

Last updated: June 12, 2026

The Cadillac CTS (2014–2019) third-generation sedan is fully keyless: the fob stays in your pocket and the car unlocks and starts on its own. When the fob coin cell goes flat the cluster reports “No Remote Detected” and the START button stops responding — but GM hides a battery-free backup in the center console, so you can still drive away.

Start the CTS With a Dead Fob: the Console Pocket

The CTS does not start by holding the fob to the button. Instead there is a transmitter pocket — a small slotted shelf with an antenna coil — at the front of the center console. Resting the fob there lets the car power and read the chip even with a dead battery.

1. Let yourself in with the metal blade (see below) and sit in the driver’s seat.
2. Open the console and find the transmitter pocket on the shelf at the front of the console bin, usually marked with a key icon.
3. Place the fob in the pocket with the buttons facing up, pushed fully home.
4. With the car in Park or Neutral, press the brake pedal and hold it.
5. Press the ENGINE START/STOP button as normal. The engine starts because the console antenna has read the fob’s transponder.

You can leave the fob in the pocket for the journey; the car only needed the chip read once at start-up.

Unlock the Door With the Emergency Key

With a dead fob the remote buttons are silent, so use the metal blade tucked inside.

1. Slide the latch on the fob and withdraw the emergency key blade.
2. The driver’s door lock cylinder is usually behind a cover on the handle — lever it off gently with the blade, or use the access notch under the handle.
3. Insert the blade and turn to unlock. If the alarm sounds, starting the car with the fob in the pocket silences it.

Why a Flat Fob Still Starts the Car

The fob contains a passive transponder that draws no current from the coin cell — it is powered by the antenna field. The radio side that normally handles hands-free entry is dead, but the console pocket sits directly over the back-up antenna, so the immobiliser handshake still completes. GM designs this into every keyless CTS as the official fallback.

Replace the Coin Cell

The pocket gets you home; swap the battery the same day so it does not catch you out again.

1. Pull the emergency key out to reveal the seam.
2. Twist the two fob halves apart using the slot or a coin.
3. The CTS fob takes one CR2032 3V lithium coin cell. Note which way up the old cell sits — positive (+) typically faces up — and fit the new one the same way.
4. Snap the halves together and refit the blade. Keyless entry should resume at once.

Frequently Asked Questions

The CTS still won’t start with the fob in the pocket. Make sure the fob is flat, buttons up, and fully seated, and press the brake firmly before START. If it still refuses, a weak 12V battery can trigger the same “No Remote” warning — check that next.

Can I hold the fob against the START button instead? No. On the CTS the back-up antenna is in the console pocket, not behind the button. Use the pocket.

Does the metal key start the engine? No. It only unlocks the driver’s door; there is no key barrel in the column. The pocket plus the START button is the only way to start.

Where is the pocket on the CTS-V? Same place — front of the center console. The high-performance CTS-V shares the identical keyless system and transmitter pocket.

How long should a CTS fob battery last? Typically three to four years. Once a “Replace Battery in Remote Key” message appears, fit a fresh CR2032 promptly rather than waiting for it to die.

If a warning light stayed on after you got going, you can look up the exact fault code on our sister site autodtcs.com to see whether it relates to the keyless system or something unrelated.