Many Toyota owners are fighting a seemingly endless battle against that dreaded AWD system malfunction 2WD mode engaged message. This means there is an issue with the vehicle’s all-wheel-drive system. Sometimes, this warning will pop up on the dashboard while driving on the highway or just after starting the engine. But in both cases, it will rarely cause any other running or performance issues.

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The all-wheel-drive system in Toyota differs significantly from the traditional 4×4 drive systems found in many vehicles. Instead of relying on the driver to engage the 4-wheel drive, this system decides when it is needed. It does this by monitoring the speed of all wheels and throttle inputs and figuring out when extra traction is required. This also means troubleshooting can be difficult or almost impossible without a diagnostic scanner that can read Toyota fault codes.

What does AWD system malfunction mean on a Toyota?

The AWD system malfunction – 2WD mode engaged warning message in a Toyota means there is an issue that deactivated its all-wheel-drive system. This may be down to an engine issue, which may be caused by something as simple as a loose gas cap. Other likely causes include a weak battery or a faulty transmission range sensor. Lastly, the AWD system will disengage if it overheats, which may be caused by a too-aggressive driving style.

Toyota AWD System Malfunction Common Causes

To help you out with this, we will go through a list of the most common problems and explain each of them. We recommend using a good scanner to run a full scan on the vehicle to find out why the malfunction is coming on the instrument cluster.

• Loose gas cap and check engine light – The AWD system in Toyota RAV4 and other similar models is designed to shut down when something triggers a check engine light automatically. One of the things that may cause this is a loose gas cap, as this offsets the operation of the EVAP system. In most cases, this will happen after filling up with gas and driving for several miles, as this is how long the system needs to detect a leak. Tightening the gas cap or replacing it if it’s damaged will solve the problem.
• Battery issues – A worn battery will cause various systems to malfunction, with the all-wheel-drive being one of them. In most cases, this happens after the battery goes flat and the driver jump-starts the vehicle. But this issue may appear with weak batteries, too, if the voltage drops low enough while cranking. If having doubts, the best thing is to measure the voltage between battery terminals using a multimeter tool.
• Faulty transmission range sensor – Like most other cars, Toyota uses a transmission range sensor to determine which gear the driver has selected. With time, these sensors wear out internally, causing the signal they send to become interrupted or incorrect. This results in shift issues or refusal to engage the selected gear. In Toyota RAV4 and other all-wheel-drive models, this issue will also trigger the AWD malfunction error. When that happens, the driver will usually not be able to start the car.
• Overheating all-wheel-drive system – If the Toyota AWD system overheats while driving, it will automatically shut down to prevent further damage. One of the causes for this may be low fluid levels inside the transmission on transfer cases. This is why it is essential to check them regularly and flush them per manufacturers’ recommendations. Another thing that can cause the all-wheel-drive system to overheat is driving style. Its components have limitations, meaning these vehicles usually can’t cope with extreme terrains.
• ABS Wheel Speed sensors – To know when to engage which mode, the Toyota all-wheel-drive system needs to know how fast each wheel is spinning. For this, it uses signals from vehicle speed sensors, which are also used by ABS and VSC safety features. If any of the four sensors fail or gets damaged, all these systems, including the AWD, will malfunction.
• Fuel Pump – Most of the all-wheel-drive models made from 2017 onwards, including the popular Toyota RAV4, have been affected by a large-scale recall in 2020. The issue was caused by a faulty fuel pump, which could deliver less gasoline than needed or completely fail. Although not directly linked to the AWD system, this problem will cause various engine issues. And if it triggers the check engine light, the AWD system will also shut down.
• Wiring and fuses – The all-wheel-drive system has several wirings, which can get damaged mechanically, by corrosion, or caused by rodents. This causes electrical shorts and various other issues, resulting in system malfunction. In addition, damaged wiring will cause corresponding fuses to blow out.

How to diagnose Toyota AWD malfunction

Use a diagnostic scanner to run a full system scan on your Toyota and find out what fault codes are present. The all-wheel-drive malfunction may be caused by something simple as a loose gas cap or dead battery, transmission range sensor, etc. The transmission range sensor is not too difficult to diagnose or replace.

But even after dealing with the suspected cause, the annoying malfunction message may still be on. This is because, in most cases, the system needs to be reset afterward. To do this, use the YOUCANIC scanner to clear the fault codes.

Frequently Asked Questions