Toyota bZ4X Owner's Manual: If Your Vehicle Overheats

When the "EV System Overheated – Output Power Reduced" message appears on the multi‑information display, it indicates that the vehicle is running hotter than normal. Immediate action is required to avoid further damage.

NOTICE: Cooling System Coolant

The radiator coolant in your vehicle is specially formulated for radiator use only. Do not substitute it with water or any other fluid, as improper coolant can damage the cooling system. If "Toyota Genuine Traction Battery Coolant" is unavailable, contact your dealer immediately.

Correction Procedures for Overheating

1. Safely pull over and turn off the air conditioning system to lessen the load on the cooling system.
2. Leave the EV system running and carefully open the hood.
3. Check that the cooling fan is operational.
   - If the fan is running: Wait for the "EV System Overheated – Output Power Reduced" message to disappear, then shut down the EV system. If the warning persists, contact your dealer.
   - If the fan is not operating: Immediately turn off the EV system and call your dealer.
4. Once the system has cooled, inspect all hoses and the radiator core for any leaks or damage.

1. Radiator
2. Cooling Fan

If you observe a significant coolant leak, contact your dealer immediately.

5. Confirm that the coolant level in the reservoir is between the "MAX" and "MIN" lines.

1. Reservoir
2. "MAX" Line
3. "MIN" Line

6. If the coolant is below the required level, replenish it only with "Toyota Genuine Traction Battery Coolant". If you do not have the proper coolant, contact your dealer without delay.

1. Remove the bolt securing the reservoir cap.
2. Open the reservoir cap slowly and carefully.

After several of these steps, have your vehicle inspected by your dealer to ensure that no further damage has occurred.

WARNING

When Inspecting Under the Hood

Do not open the hood immediately if you see steam. Wait until the steam subsides, as the engine compartment can be extremely hot and may cause severe burns.

WARNING

• Keep hands, loose clothing, or accessories (such as ties, scarves, or mufflers) away from the cooling fan. These could get caught and cause serious injury.
• Avoid loosening the coolant reservoir cap while the EV system and radiator are still hot to prevent any high-temperature steam or coolant from spraying out.

NOTICE: Adding Coolant Safely

Add coolant slowly and only after the engine and EV system have cooled down sufficiently. Rapidly introducing cool coolant into a hot system can cause thermal shock, potentially damaging internal components.

To preserve the cooling system’s integrity, ensure that no contaminants-such as dust, sand, or additives-mix with the coolant. Always use the specified coolant only.

If the Vehicle Becomes Stuck

In conditions where tires spin or the vehicle gets trapped in mud, dirt, or snow, follow these recovery procedures to safely free your vehicle.

Recovering Procedure

1. Stop the EV system immediately, set the parking brake, and shift the transmission into Park (P).
2. Clear away any mud, snow, or sand surrounding the affected tire.
3. Place traction aids-such as wood, stones, or other sturdy materials-under the front wheels to improve grip.
4. Restart the EV system.
5. Shift into Drive (D) or Reverse (R), release the parking brake, and then carefully press the accelerator while maintaining control.

When It is Difficult to Free the Vehicle

If your efforts do not yield movement, you may need to disable traction control (TRAC) by pressing the designated button (refer to your vehicle’s guide) to facilitate recovery.

WARNING

While Attempting to Free a Stuck Vehicle

If you push the vehicle back and forth to free it, ensure the area around you is completely clear of other vehicles, obstacles, and people. The vehicle may lurch unexpectedly once it begins to move.

When Changing the Shift Position

Do not shift the transmission with the accelerator pedal depressed. Inadvertent rapid acceleration can occur and may lead to an accident with severe or fatal injuries.

NOTICE

• To prevent damage to the transmission and other critical components, avoid excessive tire spinning and unnecessary acceleration. If the vehicle remains stuck after these procedures, professional towing may be necessary.

Regular awareness of your vehicle’s coolant system and recovery procedures is essential to prevent lasting damage and ensure safety on the road. For example, owners of the Toyota bZ4X can benefit from periodic maintenance checks of the cooling system and proper care when freeing a stuck vehicle. By following these comprehensive guidelines-ranging from safely addressing an overheating engine to methodically recovering from off-road entrapment-you not only protect your vehicle’s performance but also enhance your overall driving safety and experience.