Disconnect and Reconnect the Battery

Last updated: June 6, 2026

Renewing a flat battery or disconnecting for other work on your Volvo V40 (525, 2012–2019)? The 12 V battery is in the engine bay. Do it in the right order and the car relearns its settings cleanly.

Where the Battery Is

Open the bonnet — the 12 V battery sits in the engine compartment, usually under a cover. The V40 is a conventional petrol or diesel car with no high-voltage system.

Disconnecting

1. Switch everything off, remove the key and wait a couple of minutes.
2. Slacken the negative (−, black) terminal first and lift it clear.
3. Release the positive (+, red) clamp only if you’re removing the battery.

Reconnecting

1. Fit positive first, then negative, and tighten both firmly.
2. Switch the ignition on, wait, then start.

Afterwards

Re-set the clock and re-store your tyre pressures; you may also need to re-initialise the windows. Let the car sit a minute before driving.

Frequently Asked Questions

Where is the battery on a Volvo V40?

In the engine bay under a cover — a standard 12 V battery.

Which terminal comes off first?

Negative (−) off first; positive (+) on first when reconnecting.

What resets when I disconnect it?

The clock, radio presets and the tyre-pressure reference typically need re-doing.

Do I need to code a new battery?

Volvo recommends registering a new battery so charging matches it; the car runs without it, but registering preserves battery life.

This is a common job. If a warning light stays on afterwards, check the code on autodtcs.com.