These instructions apply to the Lexus CT Mk1 (ZWA10) 2011-2022. For other models, please choose your vehicle here.
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Disconnecting the 12 V battery on your Lexus CT 200h (2011–2022) — for a new battery, winter storage, or work near the airbags — catches owners out, because on this hybrid the 12 V isn’t under the bonnet, it’s in the boot.
Find the 12 V Battery First
The 12 V battery is in the luggage compartment (boot), usually on the right side under a trim panel — the under-bonnet terminals are for jump-starting only. This 12 V battery is the one you service; never touch the orange high-voltage cabling or the hybrid battery.
Disconnecting Safely
- Switch off and make sure all electrical consumers are off.
- Remove the boot trim to reach the battery, then disconnect the negative (−) terminal first, then the positive.
- Working near airbags or pretensioners? Wait 90 seconds after disconnecting before such work.
Reconnecting and Re-initialising
Reconnect positive first, then negative. The CT then relearns a few items as you drive:
- Steering angle / stability systems relearn as you drive straight and turn fully each way.
- Power windows — if one-touch is lost, pull-up-and-hold at the top to relearn.
- Re-enter the clock, presets and settings.
If Something Isn’t Right Afterwards
- Warning lights (e.g. stability/VSC) usually clear once the relearns complete after a short drive.
- A persistent light stores a code — look it up on autodtcs.com.
- Fit a like-for-like aux battery (the CT uses a specific small AGM-type).
Frequently Asked Questions
Where is the 12 V battery on a Lexus CT 200h?
In the boot (luggage compartment), usually right side under the trim — the under-bonnet terminals are only for jump-starting.
Is it safe to disconnect the 12 V on the hybrid?
Yes — the 12 V is separate from the high-voltage system; never touch the orange HV cabling.
Which terminal first?
Negative (−) off first, reconnect it last.
What needs resetting afterwards?
Steering-angle/stability relearn by driving, windows may need a one-touch relearn, plus the clock and presets.
If a warning light stays on after reconnecting, look up the code on autodtcs.com.
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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