These instructions apply to the Toyota Prius Mk1 Prius+ (ZVW40) 2012-2016. For other models, please choose your vehicle here.
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Disconnecting the 12 V battery on a Toyota Prius+ (ZVW40, 2012–2016) is a routine job for a battery change or before electrical work — but on a hybrid it’s important to know that this is the small 12 V auxiliary battery, not the high-voltage hybrid pack. The 12 V battery lives in the boot. This guide covers the safe order of work; never touch the orange high-voltage cabling.
Important: Two Different Batteries
The Prius+ has a high-voltage hybrid battery (orange cables) that powers the car, and a separate 12 V auxiliary battery that runs the computers, lights and accessories. Only the 12 V battery is owner-serviceable. Work on the high-voltage system must be left to a trained technician — do not disturb any orange cabling.
Where the 12 V Battery Is
The 12 V auxiliary battery is in the luggage compartment (boot), usually under the side trim. Lift the boot floor or remove the side panel to reach it. It’s a small AGM-type battery — fit a like-for-like replacement.
Before You Disconnect
- Note your radio/screen settings and security code.
- Make sure the car is fully off (the “READY” light off) and the key is well away.
- After switching off, wait 1 minute (and 90 seconds before handling airbags/pretensioners).
Disconnecting
- Open the boot and fold back the trim to reach the battery.
- Disconnect the negative (−, earth) terminal first and lift the lead clear.
- Only undo the positive (+) terminal (under its cover) if removing the battery completely.
Reconnecting
- Connect the positive (+) lead first, then the negative (−) earth lead last. Tighten firmly and refit the cover and trim.
- Press the START/STOP button to wake the car — it should power up normally.
What to Reset Afterwards
- Reset the date and time and reprogram your radio stations and preferences.
- Re-initialise the parking-assist system: on level ground, ignition on, parking brake on, foot on the brake, selector in P, then turn the steering wheel fully right and fully left. This relearns the steering reference the assists use.
If a Warning Light Stays On
One or two lights right after reconnecting is normal and should clear on a short drive. If a hybrid-system or other warning 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
Is it safe to disconnect the Prius+ battery myself?
Yes — the 12 V auxiliary battery in the boot is a normal lead-acid/AGM battery and safe to work on. Just never touch the orange high-voltage cabling.
Will disconnecting the 12 V battery hurt the hybrid system?
No — it just resets the computers’ volatile memory. The high-voltage pack is unaffected by 12 V work.
Do I need to register a new 12 V battery?
No coding is required — fit the correct AGM-type battery and restore your settings.
The car won’t wake after reconnecting — why?
Check both terminals are tight and the leads are the right way round. Press START/STOP without the brake to reach ignition-on first.
To clear the service reminder after maintenance, see our Toyota Prius+ 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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