These instructions apply to the Toyota Yaris Mk2 (P9) 2005-2013. For other models, please choose your vehicle here.
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Disconnecting the 12 V battery on a Toyota Yaris Mk2 (P9, 2005–2013) is a simple job for a battery change or before electrical work. There’s no dealer registration on this generation, but the power windows need re-teaching afterwards and you should note your radio settings first. This guide covers the safe order of work.
Where the Battery Is
The battery is in the engine bay. Lift any cover to reach the two terminal clamps. Fit a like-for-like replacement if you are renewing it.
Before You Disconnect
- Note your radio stations and personal settings (and any audio security code, if used).
- Turn the ignition off and remove the key.
- After switching off, wait 90 seconds before disconnecting — this lets the modules power down cleanly.
- If working near airbags or seat-belt pretensioners, allow the system to discharge before handling those parts.
Disconnecting — Correct Order
- Turn the ignition off and wait 90 seconds.
- Slacken the negative (−, earth) terminal first and lift the lead clear.
- Only undo the positive (+) terminal if you are removing the battery completely.
Reconnecting — Correct Order
- Connect the positive (+) lead first, then the negative (−) earth lead last. Tighten both firmly.
- Turn the ignition on for a few seconds before starting the engine.
What to Reset Afterwards
- Reset the date and time and re-enter your radio code, presets and preferences.
- Re-initialise the power windows — one-touch won’t work until re-taught (see our window initialise guide).
If a Warning Light Stays On
One or two lights right after reconnecting is normal and should clear on a short drive. If the airbag, ABS or engine light stays on, a fault code was logged — reading it needs an OBD scanner, and you can look up what a Toyota code means on autodtcs.com.
Frequently Asked Questions
Do I need to register a new battery on a Yaris Mk2?
No — this generation has no battery coding. Fit the correct battery and restore your settings.
Why won’t my windows go up on auto after the battery change?
Disconnecting power clears the window motors’ learned positions. Run the simple re-initialise routine and one-touch returns.
How long should I leave it disconnected?
Around 10–15 minutes with the doors shut lets the modules power down fully.
Will I lose my radio?
Some Yaris head units ask for a security code after a power loss. Have it ready, or use a memory-saver to avoid it.
To clear the service reminder after maintenance, see our Toyota Yaris service indicator reset guide.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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