Disconnect and Reconnect the Battery

Last updated: June 4, 2026

Disconnecting the 12 V battery on a Volkswagen Polo Mk6 (AW, 2018–present) is a routine job, but like its bigger Golf relative the Polo loses a few settings when the power goes and needs a couple of short re-initialisations afterwards — the one-touch windows and the steering-angle sensor. This guide gives the safe order of work and what to reset once the leads are back on.

Where the Battery Is

On the Polo Mk6 the battery is in the engine bay under a plastic cover. Lift the cover to reach the two clamps. Cars with start/stop use an AGM or EFB battery — if you are replacing it, fit the same type, as a standard battery will not survive the stop/start cycling.

Before You Disconnect

• Note your radio code and infotainment presets in case the head unit asks for them.
• Make sure the ignition is off. On keyless cars, take the fob out of the vehicle and keep it outside transmitter range so the car powers down.
• To keep settings alive, plug in a memory-saver. The steps below assume you are not using one.
• If working near airbags or seat-belt pretensioners, the battery must be disconnected before you handle those parts.

Disconnecting — Correct Order

1. Turn the ignition off and remove the key / take the fob away.
2. Open the bonnet and lift off the battery cover.
3. Slacken the negative (−, earth) terminal first and lift the lead clear, tucking it aside.
4. Only undo the positive (+) terminal if you are removing the battery completely.
5. If removing the battery, undo the base clamp and lift it out upright.

Reconnecting — Correct Order

1. Refit the battery and secure the hold-down clamp.
2. Connect the positive (+) lead first, then the negative (−) earth lead last. Tighten both firmly — a loose earth is a classic cause of random electrical faults.
3. Do not start the engine yet. Turn the ignition on (dash lit, engine off) and wait about 10 seconds for the modules to wake up.

The Wake-Up Steps Afterwards

After the power has been off, the Polo needs three quick resets:

• Reset the date and time (and re-enter the radio code/presets if asked).
• Re-initialise the electric windows — the one-touch/anti-pinch function is lost until you re-teach it. With the ignition on and doors closed, pull each window switch fully up, hold a second after it seats, then release. Full detail in our Polo Mk6 window reinitialisation guide.
• Re-initialise the steering angle sensor — after a power loss the ESC/power-steering light may show. On a level surface, drive gently straight ahead, then turn slowly to full left and full right lock; this normally re-references the sensor. If the light stays on, a VAG scan tool can perform a basic setting.

If a Warning Light Stays On

One or two lights right after reconnecting is normal and should clear within a short drive once the windows and steering angle are relearned. If an ESC, airbag or engine light remains, a fault code was logged during the power interruption. Reading it needs a diagnostic tool; you can look up what a code means on our sister site autodtcs.com.

Tools You Need

• 10 mm spanner/socket for the terminal clamps (13 mm for the hold-down).
• Optional memory-saver to preserve settings.
• Optional VAG-compatible scan tool (VCDS, OBDeleven, Carista) for a steering-angle basic setting or to clear stored codes.

Frequently Asked Questions

Will disconnecting the battery harm anything on a Polo Mk6?

No — with the ignition off and the earth lead removed first, nothing is harmed. You only lose volatile settings (clock, presets, window one-touch, steering-angle reference), all quick to restore.

How long should I leave it disconnected to reset the electronics?

For a soft reset, leave the earth lead off about 15 minutes with the doors shut so the modules fully power down. That clears most transient glitches.

Why won’t my windows auto-close after reconnecting?

Expected — the one-touch function disables itself after a power loss. Re-initialise each window and it returns.

Do I need to code a new battery?

On start/stop cars it is best to register a new AGM/EFB battery with a VAG tool so the charging system manages it correctly. Skipping it usually works but can shorten battery life.

To clear the service reminder after maintenance, see our Polo Mk6 service indicator reset guide.