“AWD System Malfunction, 2WD Mode Engaged” Error in Lexus RX 350

Your Lexus RX 350 has been reliable all year long until one day, you are taking a long trip on what seems like a fairly clear road and park for a while. Only to start your car again and meet an "AWD System Malfunction, 2WD Mode Engaged" message. 

AWD system malfunction, 2WD mode engaged message highlights

• Common reasons:electronic control problems, AWD issues
• How to fix:disconnect the battery for some time, take the vehicle in for inspection
• Possible consequences:AWD won't be working
• Priority level:High
• Can you drive?Yes
• DIY repair:Impossible
• Repair price range:$200-$2,000

How does an All-wheel Drive Work?

Unlike a two-wheel drive that powers only the front and back wheels, an all-wheel drive (AWD) system controls all four wheels. AWD cars are more common in snowy areas because the system provides better traction to ride smoothly on harsh road conditions. 

People often mistake this traction for an all-around license to drive without caution in dangerous conditions. And this ends up causing some of the most common AWD malfunctions. 

Several AWD systems have sensors that make automatic switching possible. For instance, when the system detects that one of the wheels is slipping, it powers the other wheels to keep the car going. 

Some other systems monitor the steering wheel's angle and automatically switch into AWD mode if the wheels are turned beyond normal. Turning the steering wheel beyond normal can also cause the wheels to begin to slide. 

All these should give you an idea of how important a properly-functioning AWD system is, both for your vehicle's health and safety. This also means AWD system malfunctions should never be overlooked and error messages like the one your Lexus RX350 currently has indicated a problem. 

How to Fix an "AWD System Malfunction, 2WD Mode Engaged" Error in Lexus RX 350

If you get this error message in the middle of driving, it is best to pull over at once and consult your user's manual for an idea of what to do next.

Most likely, you can manually disengage the all-wheel-drive system and keep driving in 2WD mode until you fix the issue. This depends on the terrain you are driving on. If you are sure your vehicle can handle driving in 2WD mode on a particular road, then you can go on with your trip. 

But if the terrain is jagged, you should probably call a tow truck to avoid endangering yourself while driving. Plus there is a risk of additional damage if you keep driving the vehicle despite the faulty all-wheel drive system. 

Whatever the case, there is no need to panic. This error message is a fairly common problem and might require a minor solution. Here are some possible causes of the malfunction and how to fix them.

• Poorly fitting gas cap

Remember how we talked about little errors causing an AWD system malfunction? This is one of those. Broken or ill-fitting gas caps can cause contaminants to get into the fuel tank, resulting in poor fuel economy. The solution? Tighten or replace the broken cap. This issue might seem basic but you will be surprised how it can trigger other system warnings like your check engine light turning on. 

• Faulty transmission system

Since the transmission system plays a critical role in ensuring your AWD vehicle has more grip, problems with it invariably affect the AWD system. For instance, a fluid leak is bound to affect the car and trigger the error message. Keep your ears open for a clicking sound when driving to know if the issue is with the transmission system.

The transfer case is an important part of the transmission system that holds the fluid for shifting gears. But when there is a problem with this system, changing gears would be challenging. You should check the system frequently to ensure the fluid is in check and your engine's performance is top-notch. 

• Weak battery

You might be dealing with a battery problem especially since the sensor in the warning light needs good voltage to function. A weak battery might mean less voltage is put out, making the lights an error message appear. If your vehicle is still under warranty, consider towing it back for diagnosis and repair. 

• Speed sensor errors

The speed sensors can start to malfunction when you are driving on an uneven surface. These faulty sensors affect the traction and stability of the car, also making it difficult to change gears correctly. Because of this, you should be careful about driving the vehicle when the AWD is engaged as this increases the possibility of accidents. Get an expert to fix this as the problem might require disassembling some parts of the car.

Should you Keep Driving with a "2wd Mode Engaged" Error?

Know that driving despite an AWD malfunction means that the vehicle is driving on only two wheels, rather than four. This alone tells you that 100% safety isn't assured in this state.

You should be able to continue driving your Lexus with its faulty AWD system if the road conditions are fair. That is, the weather is temperate and the terrain is smooth enough. AWD systems assist with accelerations but have little effect in helping your car stop in dangerous road conditions. 

If the indicator light comes on, that indicates a problem with the system and it might be best to stop driving. Sometimes, the light refuses to go off after you fix the issue, but a mechanic should be able to help you diagnose the fault. 

But if you must drive with the AWD light on, do so carefully and gently. Opt for routes with leveled surfaces and limit taking sharp turns or making quick stops. 

Other Error Messages to Pay Attention to

As you may find in your owner's manual, here are some other messages that may be displayed on your Lexus RX350 and solutions that can help: 

• "AWD System Overheated Switching to 2WD Mode" or "AWD System Overheated 2WD Mode Engaged"

People who drive at high speeds are more likely to encounter this error message. As simple as parking for a while or driving at a lower speed should clear the error message. If this doesn't work, reach out to your dealer to check the vehicle. 

• "A New Key has been Registered, Contact Your Dealer for Details"

You may get this message about a week from when you register a new electronic key when you open the vehicle's driver's door after unlocking it from outside. Sometimes, the message appears even though you haven't registered a new key recently. Consult your dealership to know if there's been a registration you didn't know about.

• "Headlight System Malfunction, Visit Your Dealer"

This error message often indicates a fault in any of the systems mentioned below. Have your Lexus dealer check the car to know which system might be malfunctioning: 

• The LED headlight system
• Automatic High Beam
• Adaptive Front-lighting System (AFS)
• The automatic headlight leveling system

Conclusion

Even if you are yet to experience a fault that can leave your vehicle in 2WD mode, it helps to be aware of how to deal with the situation or ways to avoid it. AWD designs offer improved traction and stability in tough driving situations but the slightest malfunction can hamper these functions. 

Drive slowly if you have to use your Lexus RX 350 when its AWD system is malfunctioning. But arrange to have a technician see the vehicle as soon as possible to avoid further damaging the car or risking your safety on the road.