Start the Car With a Dead Key Fob Battery

Last updated: June 10, 2026

The Volkswagen Polo (Mk6 / AW, 2018–Present) is sold both as a turn-key car and, on higher trims, with Keyless Access and a START/STOP button. Either way a flat fob battery is a minor inconvenience rather than a breakdown: the car’s reader coil can still read the transponder, so you can always get in and get moving.

Start a keyless Polo Mk6 with a dead fob

If your Polo has the START/STOP button (Keyless Access), the immobiliser needs the fob brought right up to the column:

1. Unlock and enter the car with the emergency blade (see below), then sit in and close the door.
2. Press and hold the brake pedal.
3. On the steering column, just below the wiper stalk, find the small indentation marked with a key symbol and a signal icon — the back-up reader coil.
4. Hold the flat of the fob against that symbol and keep it pressed there.
5. Press the START/STOP button while holding the fob in place; the engine should start.

Turn-key Polo Mk6 — the blade just starts it

If your Polo has a conventional ignition barrel rather than a START button, a dead fob battery only disables the remote-lock buttons. Pull the blade from the fob, unlock the driver’s door with it, then put it in the ignition and start the car exactly as normal — the transponder in the key head is read directly in the barrel.

Unlock the Polo Mk6 with the emergency key blade

1. Slide the release catch on the fob and pull out the metal blade.
2. At the driver’s door, prise off the lock cap on the outer end of the handle — wedge the blade into the slot at the bottom of the cap and lever it off.
3. Insert the blade into the exposed barrel and turn to unlock.

Why a flat coin cell does not strand you

The fob’s coin cell powers only the remote buttons and, on keyless cars, the proximity signal. The chip that actually proves the key is genuine is a passive RFID transponder that takes its power from the car — from the ignition barrel on turn-key cars, or from the steering-column coil on keyless cars. Neither needs the coin cell, which is why the Polo always starts one way or another.

Replace the fob battery

The Polo Mk6 fob uses one CR2032 3V lithium coin cell. Take the blade out, then ease a tape-wrapped flat screwdriver into the case seam to split it. Swap the cell with the + side facing up, snap the halves together, and refit the blade. Remote locking and keyless entry return immediately.

Frequently Asked Questions

How do I know if my Polo is keyless or turn-key?

Look at the dash: a round START/STOP button on the console means Keyless Access; a slot you insert and twist the key into means turn-key. The starting method differs between the two.

Where is the back-up reader on a keyless Polo Mk6?

In the recess on the steering column just below the wiper stalk, marked with a key and a signal symbol. Hold the fob flat against it before pressing START.

The remote buttons died but the car still starts — is that normal?

Yes, on a turn-key Polo. A flat coin cell kills only the remote locking; the key’s transponder still starts the engine in the barrel. Just change the cell at your convenience.

Which battery does the Polo Mk6 fob take?

A single CR2032 3V lithium coin cell — cheap and sold everywhere. Carry a spare if you tend to forget.

Why did the alarm go off when I used the blade?

Mechanical unlocking looks like forced entry to the car until the transponder is verified. Starting the engine cancels the alarm at once.

If a dashboard light lingered after the no-start, check the meaning on autodtcs.com to confirm it was just the fob and not an immobiliser code.