Check AWD System Meaning & Fixes

With the advent of so many types of cars that all give a versatile adventure set, it would have been beyond vulgar for carmakers like Toyota to ignore the need and desire of car enthusiasts for cars that offer a lot in the way of traction experience.

SUVs were born, and they have been making their mark on the populace for decades. As a car owner who’s used an SUV (especially if you aren’t a car enthusiast), you must have heard the acronyms “4WD” and “AWD” a lot without actually knowing the meaning. This could doubly be a problem when your “check AWD” light comes on. This would serve as an enlightenment for you.

How Does the AWD System Work and Its Benefits

AWDs aren’t only peculiar to SUVs. The AWD system is now being fitted on various cars, including sports cars and regular sedans. It is a type of wheel drive in which power from the engine is transferred to all the wheels of the vehicle to maximize traction and enable the car to function on even the most slippery of roads.

The engine power is split between both wheel axles through what is typically known as a differential, of which there are three; the central, the front, and the rear. This differential is a system that transfers power from the engine to the right axle. Some of the reasons why AWD systems improve your car’s safety include:

  • You can drive in very slippery road conditions, including mud and ice.
  • Your AWD system is an automatic system that is turned on all the time.
  • Your overall handling is very much improved. Your car handling is essentially the ease through which your car allows itself to be stabilized when it is active on the road.
  • Your AWD exponentially heightens the sportiness of your vehicle in more ways than one.

What Does the Check AWD System Mean on Your Toyota?

The “Check AWD System” warning is the car’s ability to inform you about problems relating to the AWD system. The warning comes as a message on the instrument cluster or is represented by a small light that reads “AWD” on some vehicles.

It only comes on when your AWD system is compromised or in danger of being compromised due to damage in other car parts. This warning light tells you to check your AWD system before driving the car.

Check AWD System Warning

What Can Cause the AWD Light to Come On?

There are a variety of scenarios that can make your check AWD light come on. It is important to note that if your AWD system turns off, it is most likely because the car is trying to prevent further damage to itself or when you have temporarily changed the wheels of your vehicle to a spare. Here are a few reasons why the AWD light, in particular, might come on:

01. There is a problem with the transfer case sensor and moisture

Remember that the AWD system transfers power from the engine to the tires? The transfer case and gearbox are the combinations in the car that make this possible. Typically, transfer switch settings make it possible to drive on the road. When the transfer case sensor selector has issues, the switch would most likely get stuck to one position and not shift at all.

Tire size problems

As mentioned before, your tire size is important in the equalization and function of your AWD. If the tire is too small or just doesn’t cut it, the sensor may fail to respond due to a viscous coupling and malfunctioning differentials.

Moisture and dirt

If you’re driving a sports vehicle, the chances are that you have taken it for a spin in extremely muddy or wet conditions. This won’t exactly cause a problem in the system but would cause a problem in the wiring, causing the warning to come on.

A shaft seal failure

Hydraulic pressure is needed for the functionality of the AWD, and therefore there can be no leaks. Shaft seals are the ones that keep leaks from manifesting. If you have a shaft seal problem, you should have it repaired by a car mechanic.

Fixing transfer sensor problems is easy (it’s happened to me twice in three years). You take the negative battery cable off and press the start button to get the residual power in the system out. You then take the key out and put the cable back on the battery. This method works most times.

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02. A sensor failure or loose connections at the sensors

While indirect problems of the transfer sensor like those above might cause a problem, it is also possible for problems within the sensor itself to arise. The sensor is prone to failure or might have loose wires after you’ve driven the car for a while.

The best thing to do is replace the sensor or take the car to the mechanic and troubleshoot using an OBD scanner. Sensor replacements cost around $20 to $80. You could also try to switch off the vehicle and disconnect the battery after a while to check if the error message goes away. If it doesn’t, refer to the solutions mentioned above.

Is the Check Engine Light on as Well?

Chances are, if the check engine light is on as well, the car will turn off the AWD itself to prevent further damage. This is necessary, and it is the car’s way of telling you that you have to fix the problem with the engine before the AWD (which you need to). Problems causing this might include:

Your gas cap

When the gas cap is faulty or loose, it will allow pollutants to leak into your fuel tank, causing cold running or a bad fuel economy through evaporation. The best thing to do is tighten the gas cap if it’s loose. After driving for about a hundred miles, the light should go off by itself if this was the problem.

Should the problem persist, the only alternative is to whip out your OBD scanner and read the codes. The Check Engine light is responsible for any problem with your engine and beyond, which can be rather difficult to diagnose by yourself.

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What Should I Do When It Says to Check the AWD System Comes On?

The only thing to do is to check for possible causes and fix them (possible causes have been discussed, and if you don’t think any of your issues fall into the category, you should take your vehicle to a mechanic). Your AWD is a prime function you should not allow to stay (potentially) damaged.

Can I Drive with the AWD Light On?

If you are fine with the 2WD function, you can. However, the AWD problem (especially if the check engine light is on) is indicative of a much deeper problem than just the AWD system, so you should fix or attempt to fix it before driving.

How Do You Turn Off the AWD in a Toyota Highlander?

All Toyota Highlanders are equipped with a lock AWD button. To turn on the lock mode, press this button, which will make a suspension-like icon come up on your dashboard. This will lock the center differential and distribute torque evenly across all wheels.

After you have used this button, you press the lock button back to turn it off. The system would also automatically turn off when the car exceeds 25 mph or when the brake is engaged to ensure that the ABS can do its jobs easily.

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Finishing Up

While the AWD warning message can be caused by simple things like a loose gas cap or moisture, there are more serious problems as well that can cause it. It is always recommended to start checking the easy things, and progress to more complex tasks like checking the transfer case shaft for a seal failure.