Toyota Grille Shutter Malfunction (Solved & Explained) 

A blown-out fuse and debris around the grille shutters will cause problems for the grille shutters. Malfunction sensors will not open the grille shutter and cause the engine to overheat. Also, a head-on collision could destroy the opening mechanisms for the grille shutter.

What is a grille shutter?

An engine is an unbelievably powerful machine that powers our vehicles. Without an engine, we won’t be able to drive our vehicles. We wouldn’t even be able to use the battery to listen to the radio or use the cabin lights. Because an engine is so powerful, it becomes hot very quickly. 

If there are no cooling systems inside of the engine to draw heat away, it could quickly overheat. All engines have a cooling system that uses liquid cooling. But liquid cooling is not enough. 

That is why all vehicles also have a grille shutter. When the grille shutter activates, it allows air to flow to the radiator. The air travels into the engine to push the hot air out, which also assists in cooling the engine.

There are sensors in the engine that activate and deactivate the grille shutter. When the engine is not hot enough, the grille shutters will close. When the engine is boiling hot, the grille shutters will open.

Another important feature of an active grille shutter is to reduce wind drag and increase fuel efficiency. The front part of the grille shutters remains closed. This allows the air to flow through the front of the car and escape through the sides.

What is a grille shutter malfunction?

A grille shutter opens and closes, depending on the sensors inside the engine. But a grille shutter malfunction means that the grille is not opening, is opening but not wide enough, or will not close. 

What issues cause a grille shutter inoperative and how can you fix these issues?

Incorrect engine coolant sensors.–The grille shutters rely on sensors inside the vehicle that detect the engine’s temperature. Grille shutters will automatically open if the temperature of the engine is below 40 degrees celsius. 

When the engine reaches 75C or higher, the system will automatically open the grille shutters. But if the sensors are not reporting the engine’s correct temperature to the vehicle computer system, the computer will not know to open the grille shutters. 

This is a critical issue that needs addressing immediately. If a mechanic does not fix the engine temperature sensors, the vehicle will be prone to overheating. The cost of replacing an engine temperature sensor is less than $225. 

It is best to hire a mechanic to replace the temperature sensor.

The grille shutters are stuck in the closed position – if the temperature is far too cold, less than 5° celsius, the shutters may freeze in the open or closed position. Also, Toyota designed their vehicle’s shutters to remain open when the vehicles are off. 

But a glitch or built-up debris or rest will prevent the shutters from closing when the driver turns on the engine. Perhaps the driver drove over a rocky road and there were small pedals lodged inside the grille shutters. 

Also, built-up mud and dust can clog the movement of the shutters and prevent them from closing or opening.

If you see any debris or dirt build-up in or around the shutters, remove it as best you can. But a small scrub brush and remove any debris. 

Try to remove the debris without water on the brush first. Also, you can take your vehicle to the mechanic, and they can clear the debris or pebbles for you.

A vehicular accident destroyed the grille shutters. – If you are part of a head-on collision with a vehicle or an object, the front part of your vehicle will sustain serious damage. 

Most drivers know that they will have to pay money to repair the entire front of their vehicle when they are in a collision. But even a small collision can destroy the grille shutter. 

A mechanic may be able to repair your grille shutters. But if there’s too much damage, it would be cheaper to replace the shutters than to repair them. 

The cost of a grilled shutter depends on the make and model of your vehicle. By some estimates, a grille shutter can cost up to $400 and that is just for the parts.

A blown-out grille shutter fuse – the purpose of a fuse is to lower the voltage from the power source before it reaches an apparatus or fixture. 

The grille shutters do not need much power, so a fuse diverts the strong electricity from the engine. But when the grille shutter fuse blows, there’s nothing protecting the wiring from the engine’s powerful voltage. 

Replacing a blown fuse is easy. All you have to do is check the ECU diagram to see which views belong to the active growth shutter. Then replace the other fuse with a new one. A box of fuses should not cost more than $10.

NOTE: The grille shutter malfunction will activate reduced power mode

When the power grille is not working correctly, it cannot cool the engine down. So, some critical functions will have to stop to protect the engine from overheating. 

The Grille shutter and the power control are on the same network, so they communicate with each other. If the two systems cannot communicate with each other, then the power control mode automatically reduces power to the engine. 

Not only will the power reduced mode affect the engine’s performance, but it will also affect the transmission. However, the drive can see the voltage during power reduced mode.

The driver or mechanic will be able to see if the grille shutters issue is mechanical or electrical.


An engine becomes incredibly hot, and the liquid cooling system is not enough to reduce the heat. So active grille shutters are a secondary method of engine cooling.

If the sensors in the engine do not report the true temperature, the active Grille shutter will not open. This may cause the engine to overheat. When the grille shutter is not working, the computer system would reduce the power from the engine. It is to protect the engine from overheating.

  • Eric Williams

    I'm the founder of Daily Car Tips. I wrote articles in the automotive industry for more than 10 years, published in USA and Europe. I love sharing my knowledge and insights with fellow enthusiasts. Join me on this journey as we explore the exciting world of cars together!

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