Disconnect and Reconnect the Battery

The Toyota C-HR Mk2 (2023–present) is a hybrid, so it carries two completely separate electrical systems. This guide covers the 12 V battery only — the part you can safely work on for a battery renewal, before electrical or bodywork repairs, ahead of long-term storage, or to recover the car after the 12 V has gone flat. The high-voltage hybrid battery that actually drives the car is never an owner job. Disconnect the 12 V in the right order — negative off first, positive on first — and the C-HR wakes up cleanly and relearns what it needs on the first short drive.

Two Batteries — Know the Difference

• The 12 V battery runs the lights, locks, computers and wakes the car up. It’s in the engine bay — this is the one you disconnect, and it behaves exactly like the battery in any petrol car.
• The high-voltage hybrid battery propels the car. Never touch the orange cables or any HV component — that is strictly dealer/technician territory and is not covered here.

Where the 12 V Battery Is

The 12 V battery lives in the engine bay. Lift the bonnet and look for the conventional battery with its two posts: the negative (−) earth terminal (black lead) and the positive (+) terminal under a red cover. As long as you stay on the 12 V terminals and well away from anything orange, this is a safe, ordinary job.

First, a Few Checks

• Make sure the car is fully off — not READY. The dash should be dark, with no “READY” light showing.
• Take the smart key well out of range so the car doesn’t try to wake itself while you work.
• Switch off lights, climate, wipers and the display, and close the doors.
• Wait a couple of minutes for the modules to power down, then keep clear of the orange high-voltage cabling throughout.
• Wear gloves and eye protection and have the right spanner ready before you loosen the negative terminal.

Disconnecting the 12 V Battery

1. Confirm the car is off (not READY), all electrical consumers off, and wait about a minute for the electronics to sleep.
2. Loosen and lift off the negative (−) terminal first, then tuck the lead clear so it can’t spring back.
3. If you’re removing the battery, disconnect the positive (+) next, then undo the hold-down clamp.

Stay away from the orange high-voltage cabling the whole time — you never need to go near it for this job.

Reconnecting

1. Refit the battery and clamp, then connect the positive (+) terminal first.
2. Connect the negative (−) terminal last and tighten both clamps firmly.
3. Reset the clock; the display and radio reload on their own — no code is required.
4. Press the power button to READY and check that no new warnings remain lit.

The first few stops and pull-aways may feel slightly different while the hybrid system relearns the battery state — that’s normal and settles within a short drive.

What You’ll Need to Reset Afterwards

• Clock — set it again; the radio/infotainment presets normally survive or reload automatically.
• Power windows — if auto-up/down or anti-pinch stops working, run the quick window re-initialise.
• Hybrid drive feel — give it a short drive; the engine/EV blending relearns on its own.
• Minor warning lights — several self-clear once the car completes a normal drive cycle.

If a Warning Light Stays On or the Car Feels Off

• Check both 12 V terminal clamps are properly tight — a loose earth causes most odd electrical behaviour after a reconnect.
• Take a short drive so the hybrid and driver-assist systems can relearn and settle.
• If the windows won’t auto-close, re-do the re-initialise step.
• If the 12 V keeps going flat, the small battery itself may be old or failing rather than anything you did.
• Read any stored code before replacing parts — it usually names the cause directly.

Frequently Asked Questions

Where is the 12 V battery on a Toyota C-HR?

In the engine bay, as a conventional battery with negative (−) and positive (+) posts. Disconnect the negative terminal first. The high-voltage hybrid battery is separate and is never something an owner touches.

Which terminal do I disconnect first?

The negative (−) terminal comes off first and goes back on last. That sequence avoids shorting the positive to the body while your spanner is on it, and it’s the safe order on any car, hybrid or not.

Is it safe to disconnect the battery on a hybrid?

Yes — the 12 V battery is just like any car’s and is completely owner-safe. Only the orange high-voltage system is off-limits, and you never need to go near it to disconnect the 12 V.

Does the 12 V battery need coding?

No registration or coding is required for a like-for-like 12 V battery on the C-HR. Just fit it, reconnect in the right order, reset the clock and let the car relearn over a short drive.

Will disconnecting the battery reset the service light or clear codes?

It may clear some temporary codes, but it won’t properly reset the maintenance reminder — use the correct procedure for that. Any genuine fault simply re-logs its code once the car powers back up.

Can I jump-start a C-HR from the 12 V battery?

Yes — you can receive a jump to the 12 V terminals (or the under-bonnet jump point) to wake the car, and it then starts the hybrid system itself. Never attempt to jump from the high-voltage side.

For any warning light that stays on, look up the code on autodtcs.com. To clear the maintenance reminder, see our C-HR Mk2 service reset.