Toyota bZ4X Owner's Manual: If the EV System Will Not Start

The reasons for an inoperative EV system vary, so it is essential to check each possibility and perform the corresponding procedure.

The EV system will not start despite following the correct starting procedure

The issue could be caused by one or more of the following:

• The charging cable might still be connected to the vehicle.
• The electronic key may be malfunctioning or its battery may be depleted (in which case shifting from Park could be problematic).
• The traction battery could be completely discharged – if so, charge the traction battery.
• An internal fault may exist within the immobilizer system.
• A malfunction in the shift control system may be present.
• There might be an electrical issue such as depletion of the electronic key battery or a blown fuse, which can sometimes be temporarily bypassed using an emergency start procedure.
• The traction battery temperature could be extremely low (below approximately -22ºF, or -30ºC).

The interior lights and headlights are dim, or the horn sounds faintly

This symptom is usually due to one of the following:

• The 12‑volt battery might be discharged.
• The 12‑volt battery terminals may be loose, corroded, or even disconnected.

If the interior lights, headlights, or horn do not work at all, the likely causes remain a discharged battery or disconnected terminals. In every case, if you cannot resolve the problem through these checks, contact your Toyota dealer.

Starting the EV System in an Emergency

As an interim measure when the EV system refuses to start (and assuming the power switch is functioning normally), follow these steps-but use this procedure only in emergencies:

1. Set the parking brake firmly.
2. Turn the power switch to the ACC setting*.
3. Press and hold the power switch for about 15 seconds while firmly depressing the brake pedal.

Even if the system starts using these steps, it indicates that an underlying malfunction may exist. Have the vehicle inspected by your dealer as soon as possible.

*Note: The ACC setting can be customized per vehicle configuration.

If You Lose Your Keys

New genuine keys can be produced by your Toyota dealer using the spare key and the key number stamped on your key number plate. Keep this plate in a secure place-such as your wallet-instead of leaving it in the vehicle.

NOTICE

When an electronic key is lost, the risk of theft increases dramatically. Bring all remaining electronic keys provided with your vehicle to your dealer immediately.

If the Electronic Key Does Not Operate Properly

Disrupted communication between the key and the vehicle – or a situation in which the key cannot be used due to battery depletion – will render the smart key system and wireless remote control unusable. In this event, the doors can still be opened and the EV system started by following a specific procedure.

When the Electronic Key Does Not Work Properly

• Verify that the smart key system is activated in the customization settings. If it has been turned off, reactivate the function.
• Check whether the battery-saving mode is enabled. If it is, disable it.

NOTICE

In the event of a smart key system malfunction or other key-related issues, take your vehicle along with all the electronic keys provided with it to your dealer immediately.

Recommendations

Regular diagnostic checks and prompt attention to key and EV system warnings are vital for maintaining vehicle reliability and safety. For instance, owners of the Toyota bZ4X benefit greatly from addressing any sign of electrical or key system malfunction as soon as it occurs. By following the proper procedures detailed above and consulting your dealer when necessary, you help ensure that your vehicle remains safe and fully operational.

Locking and unlocking the doors

Use the mechanical key  in order to perform the following operations.

1. Locks all the doors
2. Unlocks the door

Turning the key rearward unlocks the driver's door. Turning the key once again within 5 seconds unlocks the other doors.

Key linked functions

1. Closes the windows (turn and hold)*
2. Opens the windows (turn and hold)*

*: These settings must be customized at your Toyota dealer.

WARNING

When using the mechanical key and operating the power windows

Operate the power window after checking to make sure that there is no possibility of any passenger having any of their body parts caught in the window. Also, do not allow children to operate the mechanical key. It is possible for children and other passengers to get caught in the power window.

Starting the EV system

1. Depress the brake pedal.
2. Touch the electronic key to the power switch.

When the electronic key is detected, a buzzer sounds and the power switch will turn to ON.

When the smart key system is deactivated in customization setting, the power switch will turn to ACC.

3. Firmly depress the brake pedal and check that is displayed on the multi-information display.
4. Press the power switch shortly and firmly.

In the event that the EV system still cannot be started, contact your Toyota dealer.

Stopping the EV System

To safely turn off the EV system, ensure the shift position is set to Park (P), engage the parking brake, and press the power switch as you normally would. Following these steps helps maintain system integrity and ensures a smooth shutdown.

Replacing the Key Battery

If you've used the emergency procedure to start the EV system, remember that this is only a temporary solution. It's highly recommended to replace the electronic key battery immediately once depleted to restore normal smart key functionality.

Alarm System Activation

If a door is unlocked using the mechanical key while the alarm system is engaged, the alarm may be triggered. To prevent unnecessary alarm activation, use the electronic key whenever possible.

Changing Power Switch Modes

If you need to toggle through the power switch modes without starting the EV system, simply release the brake pedal and press the power switch. Each time you press the switch, the mode will cycle, allowing you to access auxiliary power functions without activating the drive system.

Final Recommendations

Maintaining proper shutdown procedures and key functionality ensures that your EV system remains reliable and secure. Owners of the Toyota bZ4X can optimize their vehicle's performance by regularly replacing key batteries, following correct shutdown methods, and being aware of alarm system triggers. Taking these small but crucial steps contributes to a seamless and hassle-free driving experience.