Replace the Key Fob Battery

Last updated: June 6, 2026

A Volkswagen Polo Mk6 (2018–present) remote that has to be waved right at the car, or that ignores the odd press, is almost certainly running on a dying coin cell rather than failing electronics. Swapping it takes a few minutes with nothing more than a small screwdriver, and the Polo even lets you re-pair the remote at the door if it has lost sync. This guide walks through both, and explains why a brand-new key is a different matter.

Start With the Cheap Fix

The sixth-generation Polo carries the current VW flip key with a CR2032 cell. Because a weak cell is by far the most common cause of short range or a dead button, fit a fresh one before assuming the worst. The pull-out metal blade always unlocks the driver’s door, so a flat fob never strands you.

Replacing the Fob Battery

1. Slide out the key blade with the release button; the case seam is now accessible.
2. Lever the cover off with a small flat screwdriver at the seam.
3. Press a button on the remote to drain residual charge, then remove the old CR2032.
4. Fit the replacement the correct way up (match the old cell), keeping fingers off the faces.
5. Close the case, refit the blade, and confirm lock/unlock works.

Re-synchronising the Remote

If the buttons stay dead after a new cell, re-register the remote at the driver’s door — the exact routine VW documents for the Polo:

1. Remove the lock cover on the driver’s door handle to expose the barrel.
2. Insert the blade into the lock.
3. Press unlock on the remote, then turn the key to unlock within one minute.
4. The key is registered — test the buttons.

Lost Key or Adding a Spare

The steps above are for a fob the car already knows. Pairing a new key or remote runs through the Polo’s immobiliser and needs VW dealer or locksmith tooling — there is no DIY button sequence for a fresh transponder.

If It Still Won’t Work

• Double-check polarity and clean the contacts — the usual reasons a swap doesn’t take.
• Try the second key — if it behaves, the first fob’s board may be at fault rather than the car.
• No remote at all? A central-locking or receiver fault may have logged a code you can decode on autodtcs.com.

Frequently Asked Questions

Which battery fits the Polo Mk6 key?

A CR2032 coin cell — verify against the old cell when the fob is open.

Do I need to recode the key afterwards?

No. The coding is retained; only a lost-sync remote needs the door resync above.

Can I add a new Polo key without a dealer?

No — a new transponder must be coded with VW equipment because of the immobiliser.

Is the keyless Polo fob the same swap?

Yes — keyless-entry fobs still take a CR2032 and open the same way.

Changing the fob battery as part of a wider job? See our Polo Mk6 battery disconnect/reconnect guide for the related resync.