Disconnect and Reconnect the Battery

Last updated: June 5, 2026

Disconnecting the 12 V battery on a Toyota C-HR (2016–2023) is a straightforward job, but there are a couple of Toyota-specific steps worth knowing — open the windows first so you are not locked out, and re-initialise the steering angle (and powered tailgate, if fitted) afterwards. This guide covers it.

Where the Battery Is

The battery is in the engine bay. Lift any cover to reach the two clamps. This guide is for the petrol/1.2T C-HR’s 12 V starter battery (the hybrid’s separate high-voltage system is not covered here). Fit a like-for-like replacement if renewing.

Before You Disconnect

• Open the windows first. With the power off, the central locking and keyless entry won’t work — having the windows down means you can always reach in.
• Check your audio system security code and note your presets.
• Turn the ignition off, ensure all consumers are off, and wait about 1 minute before disconnecting.
• To keep settings alive, plug in a memory-saver. The steps below assume you are not.
• If working near airbags or seat-belt pretensioners, disconnect the battery and wait at least 2 minutes before handling those parts.

Disconnecting — Correct Order

1. Turn the ignition off and take the smart key away from the car.
2. Open the bonnet and reach the battery.
3. Slacken the negative (−, earth) terminal first and lift the lead clear.
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.
3. Turn the ignition on for a few seconds before starting the engine.

What to Reset Afterwards

• Enter the radio code if asked, and reset the date and time and presets.
• Re-initialise the steering angle sensor — drive gently straight, then a slow full-left and full-right turn; the warning light should clear.
• Re-initialise the powered tailgate if fitted — simply unlock the tailgate with the key/fob to re-sync it.
• Re-store the tyre pressures if the TPMS light comes on (see our C-HR TPMS reset 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 remains, a fault code was logged. Reading it needs an OBD scanner — you can look up what a C-HR code means on our sister site autodtcs.com.

Tools You Need

• 10 mm spanner/socket for the terminal clamps and hold-down.
• Optional memory-saver to preserve presets and settings.
• Your radio keycode, if the head unit is code-protected.

Frequently Asked Questions

Why open the windows before disconnecting the C-HR battery?

With no power the central locking and keyless entry stop working — open windows mean you can always reach the door handle, so you don’t get locked out.

Do I need to register a new battery on a C-HR?

No coding is required on the petrol C-HR — fit a like-for-like battery, reconnect, and re-initialise the steering angle and tailgate.

Why is the ESC/steering light on after the battery change?

The steering-angle sensor lost its zero point. The simple steering left/right relearn re-references it and the light goes out.

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

Around 15 minutes with the doors shut lets the modules power down fully.

To clear the service reminder after maintenance, see our Toyota C-HR service indicator reset guide.