Start the Car With a Dead Key Fob Battery

Last updated: June 12, 2026

The Peugeot 3008 (Mk2/P84, 2016–Present) — including the 3008 Hybrid and Hybrid4 — carries Peugeot’s keyless “Access & Start” on most trims. When the fob coin cell dies, the doors stop responding and the START/STOP button shows “key not detected”. It mimics a flat car battery, but it is only the fob. The key keeps a battery-free transponder the 3008 can read at close range, so you can open it and drive away.

Entry trims with a plain remote and turn ignition aren’t affected for starting — a dead fob just disables the remote buttons; unlock with the blade and turn the key. The steps below are for keyless cars.

Start the keyless Peugeot 3008 Mk2 with a dead fob

1. Open the car with the emergency blade (next section), sit in the driver’s seat and close the door so the cabin antenna can search for the key.
2. Press and hold the brake pedal — the 3008 will not start without it.
3. Press the START/STOP button once. The i-Cockpit cluster shows “key not detected”.
4. Hold the flat face of the fob against the steering column, just left of the START button, over the backup antenna where the ignition barrel sits on a non-keyless 3008.
5. With the fob held there and the brake pressed, press START/STOP again. The immobiliser powers the passive chip, recognises the key and the engine starts. On the Hybrid, it goes to READY.

Unlock the doors with the emergency key blade

1. Slide the catch on the fob and pull out the metal emergency blade.
2. Lever off the small cover at the rear of the driver’s door handle with the blade tip to expose the hidden lock cylinder.
3. Insert the blade, turn to unlock, then refit the cover. The alarm may sound until the car recognises the key and starts.

Why this works — the immobiliser note

The 3008 Mk2 fob holds a battery-powered radio for hands-free locking and a passive RFID transponder powered wirelessly by the car. A flat CR2032 only kills the radio; the transponder still answers the immobiliser when held within a few centimetres of the column antenna. That is exactly why holding the fob to the column starts a 3008 with a dead cell.

Replace the fob battery

The Peugeot 3008 Mk2 fob takes a single CR2032 3V lithium coin cell. Remove the emergency blade, split the case at the seam, lift the old cell out and fit the new one with the + face up, then clip it shut. A fresh CR2032 lasts two to three years; once keyless range drops off, change it before it leaves you holding the fob to the column.

Frequently Asked Questions

Does the 3008 Hybrid use the same method? Yes. Hold the fob against the steering column and press START/STOP with the brake down to bring the Hybrid to READY.

Where exactly do I hold the fob? Flat against the left of the steering column by the START button. If it doesn’t catch first time, shift the fob a centimetre and press START/STOP again.

Why can’t I find the door keyhole? It is capped for a clean handle. Prise the small cover off the end of the driver’s door handle with the blade to reach the cylinder.

What battery does the 3008 fob take? A CR2032 lithium coin cell, available in any supermarket and swapped in under five minutes.

The alarm sounded when I used the blade — is that a fault? No. Mechanical entry trips the alarm by design and it silences as soon as the car reads the key and starts.

If a warning light or fault code appeared with the key message, you can decode it on our sister site autodtcs.com.