Start the Car With a Dead Key Fob Battery

Last updated: June 11, 2026

Dacia Duster (Mk2, 2018–Present) uses a conventional remote key fob rather than the Renault keycard, but the principle is the same when the battery dies: the transponder chip inside the fob needs no battery to start the engine, so a flat fob will not strand you. How you start depends on whether your Duster has keyless push-button start or a traditional turn key, and this guide covers both, plus how to get into the car with the emergency blade.

Starting the Duster Mk2 with a dead key fob

Identify your ignition type first. Keyless Duster trims have a START/STOP button; lower trims have a key barrel you turn.

1. Unlock and enter the car using the emergency key (see below) if the remote will not respond.
2. If your Duster has push-button start: hold the key fob against the START/STOP button, or against the keyless reader icon near the gear lever between the seats, press the brake pedal, then press START. The car’s antenna powers the fob chip and the engine starts.
3. If your Duster has a turn-key barrel: simply insert the cut metal key into the ignition and turn it. The barrel reads the transponder directly, so a dead fob battery makes no difference.
4. On a keyless car, keep the engine running until you have changed the battery, since a dead fob may not be detected to restart.

Unlocking the door with the emergency key

With a flat fob battery the remote buttons stop working, so use the metal blade inside the fob.

1. Slide the catch on the fob and pull out the integrated emergency key blade.
2. Go to the driver’s door. The lock barrel may be hidden under a cap on the handle on some trims.
3. Remove the cap if fitted to expose the lock.
4. Insert the blade and turn to unlock. The alarm may sound and stops once you start the car with the fob present.
5. Push the blade back into the fob before driving.

How the fob transponder works

The Duster fob contains a battery-powered radio for the remote lock and unlock buttons, plus a separate transponder chip that runs without any battery. On keyless cars, holding the fob at the START button or the marked reader near the gear lever places the chip in the car’s antenna field, which powers it long enough to read its code. On turn-key cars the barrel reads the chip directly. Either way a dead fob still starts the Duster, it just can no longer lock or unlock the doors by remote.

Replacing the key fob battery

Most Duster Mk2 fobs use a CR2032 3V coin cell, though some early units use the thinner CR2025. Check the cell you remove and match it; never force a thicker CR2032 into a CR2025 slot.

1. Slide out the emergency key blade to release the fob case.
2. Split the case at the seam, or unclip the cover, to reach the battery.
3. Remove the old cell and fit the matching CR2032 (or CR2025) with the correct polarity.
4. Clip the case back together and reinsert the blade.
5. Press a fob button next to the car to confirm the remote works again.

Frequently Asked Questions

Can I start my Duster with a dead fob? Yes. On keyless cars hold the fob at the START button or the reader by the gear lever; on turn-key cars just use the cut key in the barrel.

Which battery does the Duster Mk2 fob use? Usually a CR2032 3V cell, but some early fobs use the thinner CR2025. Match what you remove.

Where is the keyless reader zone? On keyless trims it is marked near the gear lever between the front seats; hold the fob there if the START button alone does not respond.

Can the emergency blade start the engine? On keyless cars no, the fob must be present. On turn-key cars the cut key itself starts the car because it carries the chip.

Will the alarm go off when I use the blade? It can, because the remote is bypassed. It stops once the car detects the fob and starts.

If a warning light or stored fault code appears after the fob goes flat, you can decode it on autodtcs.com.