Let us set the scene: the great outdoors, picturesque views, and the rumbling engine of a Toyota Highlander tearing through terrain that’s off the beaten path.
But then suddenly, your wheels lose traction, you get stranded in the mud, and a “Check AWD system” message pops up on your Highlander’s screen.
Having driven the Toyota Highlander on adventures before, we’re all too familiar with this notorious message on the crossover SUV, and this guide will walk you through what it exactly means and how to fix it!
What does “Check AWD System” mean on a Toyota Highlander?
The “Check AWD System” message appears on the Toyota Highlander’s dashboard as a warning that there is an issue relating to the AWD system.
It can be caused by a fault or malfunction in the AWD system itself, transmission-related problems, the ignition system remaining on, or faulty speed sensors.
The Toyota Highlander’s modern AWD system has its own way of notifying you whenever the ECU, or the SUV’s computer/brain, suddenly detects a problem that can potentially spell trouble for the said system.
Right in between the two gauges of your Toyota Highlander’s dashboard, you can receive a small message on the screen that simply tells you to check your AWD (all-wheel drive) system.
While literally checking your AWD system is easier said than done, this is actually more of a warning that is meant to prompt you to have the system looked at by your local Toyota dealership or trustworthy mechanic.
What is the Toyota Highlander’s AWD System?
The Toyota Highlander’s AWD (All-Wheel Drive) System allows the SUV to switch from FWD (front-wheel drive) to AWD mode with a push of a button.
The AWD system utilizes a 50:50 torque split for the front and rear wheels, making it suitable for off-roading or other situations where more grip is needed.
While all-wheel drive (AWD) systems have been around as early as the 1900s, the advancement of automotive technology has given rise to more sophisticated forms of it in today’s vehicles.
Such is the case for the Toyota Highlander crossover SUV, which comes with an optional AWD system for certain trims that takes its standard front-wheel drive (FWD) layout and distributes 50% of the engine’s torque to the rear wheels.
This is known as a “50:50 torque split”, which is quite a common way that power is distributed in AWD-equipped SUVs.
However, it’s worth noting that the 50:50 torque split in the Toyota Highlander and many other AWD vehicles only happens under normal driving conditions, or to put it more specifically, when all four wheels have equal amounts of grip on the road surface.
Hence, under conditions where one or more wheels may lose some grip on the surface, such as when traversing off-road terrain, the AWD system can actually adjust the amount of torque transferred to each individual wheel or axle as needed.
In the case of the Toyota Highlander’s AWD system, this is where its “Dynamic Torque Vectoring AWD” technology can come into play.
As its name suggests, the Toyota Highlander’s Dynamic Torque Vectoring AWD system constantly adapts to road or terrain conditions so that optimal traction is maintained at all times.
This also makes it sort of a safety feature, especially when you’re driving on any slippery surface where your vehicle’s tires might potentially lose traction.
Furthermore, this type of AWD technology can also help prevent you from getting stuck in the sand or mud, as the system can quickly detect that one or more wheels may be slipping or spinning in place.
Even when on dry pavement, the Toyota Highlander’s AWD system still constantly adjusts the amount of torque on each wheel while cornering, resulting in more responsive handling.
What causes the “Check AWD System” on a Toyota Highlander?
The Toyota Highlander’s “Check AWD System” message can be caused by the AWD system not working, issues with the transmission system, malfunctioning speed sensors, and the ignition system staying on.
Several different issues can cause the “Check AWD System” notification to appear on the Toyota Highlander, but of course, one of the most obvious ones by default would be the AWD system itself not working or malfunctioning.
However, there are other common reasons that trigger the notification to appear that don’t directly involve the AWD system feature, such as transmission issues, faulty speed sensors, and the ignition system remaining on while the SUV is already running.
Hence, we’ll be dissecting each of these causes as well as providing you with potential solutions for them one by one below.
AWD System Not Working
Whenever you get a message like “Check AWD System” or something along those lines in any vehicle, then common sense would tell you to assume that it involves the component mentioned in the message.
Thus, one of the most common reasons why the message shows up is that there has been a problem detected on the AWD system, resulting in the deactivation of the system to preserve its components.
In some cases, the AWD system may even completely stop working altogether suddenly, which will perpetually leave you in front-wheel drive (FWD) mode only unless you get to the bottom of the issue.
| The AWD system failure has since been attributed to more specific issues such as a leaking clutch, a worn-out clutch differential, and improper refueling after swapping out the gaskets and pumps, which can all trigger the message or light to appear. |
Other owners have even experienced the “Check AWD System” message disappearing before they can have it checked by the dealership, only for it to come back one day later.
Thus, before you have the problem properly diagnosed by your local Toyota dealer and have any affected parts replaced, we recommend taking a photo or video of the message as evidence of the issue.
Transmission System Issues
An issue that concerns the Toyota Highlander’s transmission system can also be one potential reason for the “Check AWD System” light or message to pop up on the dashboard.
Since the transmission system has a major role to play in a vehicle’s drivetrain, any kind of fault that involves it can also affect how the AWD system distributes power to the wheels.
For instance, if the transmission system is leaking fluid, there’s a chance that there will not be enough lubrication for it to transmit power and shift gears smoothly.
As a result, the entire AWD system’s performance can be compromised and you may even hear a grinding noise from the transmission gears due to reduced lubrication.
In other instances, transmission system issues aren’t exactly caused by a leak, but by simply having transmission fluid that’s already too dirty and overdue for a change.
On that front, the manufacturer recommends changing the Toyota Highlander’s transmission fluid every 30,000 miles (48,000 km).
This also applies when changing the fluid or oil of the transfer case, an important drivetrain component that makes sure the AWD system engages and disengages properly.
Another thing that can negatively affect the transmission system of the vehicle is using mismatched tire sizes, as it can cause the wheels to roll at different speeds while you’re driving.
Hence, this is one of the reasons why it’s recommended to change all four of your tires at exactly the same time to ensure they actually come from the same set.
Malfunctioning Speed Sensors
Another possible cause of the “Check AWD System” message that doesn’t necessarily involve the mechanical components of the drivetrain is the malfunctioning of the speed sensors.
The Toyota Highlander and many other vehicles of today come with speed sensors that are able to provide data about the current speed, distance traveled, and optimal shifting RPMs to the SUV’s computer.
But despite the speed sensors being electronic components, they are still attached to the Toyota Highlander’s rear axle underneath the vehicle, making them rather exposed to the elements, especially while off-roading.
In this way, there is a chance that the speed sensors can start to malfunction and display either incorrect data or no data at all on your dashboard gauges.
Due to the incorrect data (or lack thereof) being sent to the computer, the vehicle’s AWD system will not be able to do its job down to a T when engaged. This is the time when the message to check your AWD system then appears.
When this happens, be sure to not use the vehicle on slippery roads or terrains in the meantime to avoid potentially causing more damage to drivetrain components.
Afterward, have the speed sensors looked at by a certified mechanic or technician for any faults. While you’re at it, get other related drivetrain components checked as well for good measure.
Ignition System Stays On
One problem that you probably don’t expect can trigger the “Check AWD System” light or message is the ignition system staying on even if the engine has already been successfully started.
The ignition system is only supposed to be activated as the engine is being cranked to start, then stops when the engine has already “turned over” and can continuously run by itself after initial ignition.
However, the Toyota Highlander’s ignition system is known to stay on due to an overheating issue in the engine’s combustion chamber, which in turn, can be traced to bad spark plugs.
As the ignition system continually operates for prolonged periods of time, it can be akin to holding the key in the “Start” position while the engine is already running, which can cause the starter motor to overheat.
Furthermore, during ignition, the starter motor connects a separate gear and the transmission’s flywheel or torque converter so that they both rotate until the engine can take over.
The problem is that when the ignition still continues after this point, the gear and the flywheel or torque converter don’t get disconnected while the latter is already being run by the engine.
This can potentially result in increased wear and even grinding among the components depending on how long the ignition system stays on. Thus, the check AWD system warning light or message appears to notify you.
If you’re experiencing this kind of issue, be sure to have your ignition system components immediately checked for possible replacement, before it starts affecting other major components of your engine and drivetrain.
What to Do When the Toyota Highlander’s “Check AWD” Light Turns On
If the Toyota Highlander’s “Check AWD System” light or message pops up on the dashboard, avoid driving the vehicle off-road, on uneven terrain, and up inclines.
Have the check AWD system issue diagnosed by your local dealer or mechanic so that they can look for fault codes that may explain it.
Sometimes, the “Check AWD system” message may even disappear before you could have a professional look at it. So for this reason, we recommend taking a photo or video of the message for evidence.
After getting it diagnosed, the mechanic will be able to tell what’s causing the AWD system light to turn on and inform you of the necessary steps to resolve it.
Is it safe to drive with the Toyota Highlander’s “Check AWD” light on?
It’s still safe to drive the Toyota Highlander for a while even with the “Check AWD” light on. However, you should avoid driving the vehicle off-road or on any terrain that demands more from both the engine and drivetrain.
With that said it’s still highly recommended that you have the warning light immediately checked by a mechanic, especially if the light doesn’t go away even after turning off the vehicle and turning it on again.
Frequently Asked Questions (FAQs)
