Disconnect and Reconnect the Battery

Last updated: June 5, 2026

Disconnecting the 12 V battery on a Honda HR-V Mk2 (RU, 2015–2022) is a routine job for a battery change or before electrical work, but like other Hondas of this era you really do need your radio security code ready — the head unit locks after a power loss. This guide covers the safe order of work and what to reset once the leads are back on.

Where the Battery Is

The battery is in the engine bay. Lift any cover to reach the two clamps. Fit a like-for-like replacement if you are renewing it — match the original specification.

Before You Disconnect

• Note your audio system security code — it is needed after a power loss (owner’s wallet card, the unit serial, or a Honda dealer).
• Note your preset stations and user preferences.
• Turn the ignition off and remove the key (or keep the keyless fob away from the car).
• After turning the ignition off, wait 3 minutes before disconnecting — this lets the modules power down (and is essential before handling airbags or pretensioners).
• To keep settings alive, plug in a memory-saver. The steps below assume you are not.

Disconnecting — Correct Order

1. Turn the ignition off and wait 3 minutes.
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. Check the terminal connectors are clean; a little grease helps keep water out.
2. Refit the battery and secure the hold-down clamp.
3. Connect the positive (+) lead first, then the negative (−) earth lead last. Tighten both firmly.
4. Turn the ignition on for a few seconds before starting the engine.

What to Reset Afterwards

• Enter the radio code when prompted.
• Reset the date and time and re-enter your presets and user preferences.
• Re-initialise the tyre-pressure (Deflation Warning) system — once your pressures are correct, run the initialise routine from the menu (see our HR-V TPMS reset guide).
• If the power windows stop auto-closing, hold each switch fully up for a moment to re-teach the closed position.

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 an HR-V 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 the radio code and settings.
• Your radio security code.

Frequently Asked Questions

Will I lose my radio after disconnecting the battery?

The unit locks and asks for its security code after a power loss. Have the code ready, or use a memory-saver to avoid it.

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

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

Why does the tyre-pressure light come on after the battery change?

The Deflation Warning System loses its baseline; re-initialise it from the menu once your pressures are correct.

Do I need to register a new battery on an HR-V Mk2?

No coding is required — fit a like-for-like battery and enter the radio code afterwards.

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