Start the Car With a Dead Key Fob Battery

Last updated: June 12, 2026

The Cadillac ATS (2013–2019) is a keyless Passive Entry/Passive Start car: you keep the fob in your pocket and the sedan or coupe unlocks and starts on its own. When the fob’s coin cell dies, the dash throws a “No Remote Detected” message and pressing the START button does nothing — but GM built a battery-free backup into every ATS, and it does not rely on holding the fob against the button.

Start the ATS With a Dead Fob: the Transmitter Pocket

Unlike many rivals, the ATS does not start by touching the fob to the button. Instead GM hides a transmitter pocket — a small slot with an induction antenna — inside the center console. Resting the fob there lets the car energise the chip and read it even with a flat battery.

1. Get in first using the metal blade (see below) and sit in the driver’s seat.
2. Open the center console armrest and look for the transmitter pocket: on the ATS it sits at the front of the console bin, opposite the USB ports, often marked with a key symbol.
3. Lay the fob flat in the pocket, buttons facing up, pushing it as far in as it will go.
4. With the car in Park, press the brake pedal fully and hold it.
5. Press the ENGINE START/STOP button as you normally would. The engine cranks and starts because the console antenna has read the fob’s transponder.

Leave the fob in the pocket until you reach your destination; the car only needed the chip read at start-up, but there is no harm in leaving it there.

Unlock the Door With the Hidden Key Blade

A flat fob will not pop the locks by radio, so the ATS fob carries a removable metal key.

1. Slide the release latch on the fob and pull the emergency key blade straight out.
2. On many ATS cars the driver’s door lock is concealed behind a cap on the handle — ease it off, or use the slot on the underside of the handle to reach the cylinder.
3. Insert the blade and turn to unlock. The alarm may sound; starting the car with the fob in the pocket clears it.

Why the Immobiliser Still Lets You Start

The fob holds a passive transponder that needs no battery — it is powered by the antenna’s magnetic field. The radio link that handles normal hands-free entry is dead, but the console pocket sits right over that antenna, so the immobiliser handshake completes and the ATS starts. This is a deliberate, designed-in fallback, not a workaround.

Replace the Coin Cell

The pocket gets you moving, but fit a fresh battery the same day.

1. Pull the emergency key out to expose the seam in the fob.
2. Use the slot, or a coin, to twist the two halves apart.
3. The ATS fob uses a single CR2032 3V lithium coin cell. Note the orientation — positive (+) usually faces up — and fit the new one the same way.
4. Clip the halves together until they click and reinsert the blade. Hands-free entry should work again immediately.

Frequently Asked Questions

My ATS shows “No Remote Detected” even with the fob in the pocket. Reseat the fob flat and fully home in the pocket, then press the brake firmly before START. If it still fails, suspect the 12V battery, which can throw the same message when low.

Can I just hold the fob against the START button like other cars? No — the ATS antenna is in the console pocket, not behind the button. The pocket is the official backup; touching the fob to the button does nothing on this car.

Will the metal key start the car? No. The blade only unlocks the driver’s door; there is no ignition barrel. Starting always goes through the pocket and the START button.

Where exactly is the transmitter pocket on a coupe? Same location as the sedan — front of the center console bin under the armrest. If you cannot find a marked slot, the cupholder area or console tray over the antenna can also work on some builds.

Does this work on the ATS-V? Yes. The performance ATS-V uses the same keyless system and the same console transmitter pocket.

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.