Service AWD Light: Causes and Fixes

Follow me as I walk you through everything you need to know about the AWD system. When the AWD indicator light comes on and won’t go off, you need to check for a few causes. This article has got you covered in this area. You’ll also learn a lot of other things about the service AWD system in its entirety. 

Let’s get started

What is AWD System and How Does it Work?

As the name suggests, AWD is a contraction for All-Wheel Drive. Modern automakers build the AWD system into the car transmission system to empower the back and front wheels. Generally, AWD-enabled cars boast an amazing design that includes more durable suspension than a 2WD.  

The overall idea is to reinforce your car tire’s grip on the terrain while improving traction. As a result, you can be sure of enhanced car performance on the pavement and at top speed. 

In addition, an AWD system is an automatic car part that helps reduce the risk of collision. It doesn’t matter if you drive on muddy, rough, or snow-covered roads. With the AWD system, you’ll be able to handle your car. Plus, stability and sportiness significantly improve. 

Typically, when the service AWD warning appears steady, it indicates that the AWD system is engaged. However, when the light is blinking, it means that the service AWD system is overheating. There are reasons why the system will overheat or not function properly. I’ll come back to these shortly. But suffice it to say that every blinking AWD light requires immediate attention and service.     

Why Service AWD Light Comes On 

As I said earlier, whenever you observe a blinking AWD light, it’s an indication of a mild or severe system issue. Here are some possible causes:  

Driving on Compact Spare Tires

Unlike donut tires, compact spare tires are intended for emergency or low-speed driving. These compact tires can cause poor traction and negatively impact control, handling, and ABS. Once the tires affect these features, the AWD light will mostly likely blink, come on, and go off. If you use spare tires of different sizes other than what is recommended or provided in the manual, you may face a similar problem. 

The AWD light will turn off temporarily. Consequently, it’ll enter a front-wheel mode in order to protect your vehicle’s driveline parts. When this happens, you’ll get a message in the information screen, warning you of a disabled AWD.  

How to Fix?

Under normal circumstances, you shouldn’t use a compact spare tire for more than 50 miles and not drive above 50 miles. Anything more could cause serious damage. The best thing to do once you notice that your vehicle is losing traction control is to replace the tire.  

Dissimilarity in front and rear axles

In addition, the indicator light will automatically turn off due to observable dissimilarity in the tire sizes between the rear and front wheel axles. This is almost similar to the first reason I identified, but with a little difference. This usually happens after you’ve reinstalled or replaced with a new recommended tire. Note that after replacement, you may need to cycle the ignition on and off. 

How to Fix?

The proper remedy is to install the right tire size that matches the other three tires during replacement. I’m sure you don’t want your car to return to and remain in front-wheel drive. Driving with a damaged AWD system won’t be a good idea, either. 

Speed Sensor or Transmission Issue 

A failure of the speed sensor can cause the speedometer not to send any signal about your car’s speeds. A degraded speed sensor can come from poor driving conditions, including prolonged exposure to the elements. It could also be due to a hilly or mountainous surface. Consequently, as you engage the AWD with a malfunctioning speed sensor, the AWD light may come on and go off intermittently. The indication might be that your car has lost stability and traction controls.  

How to Fix?

The simple answer is, ‘fix the sensor.’ You can either repair or replace it, but I’ll recommend the latter fix. But first off, don’t drive if the speed sensor malfunctions with the AWD system engaged. Fixing a speed sensor isn’t a walk in the park. You may need to call a certified mechanic as it requires dissembling some sensitive parts of your car.  

AWD system is Overheating

An overheated AWD system can also be responsible for a fluctuating service AWD light. One major reason your car’s AWD system will overheat is severe operating conditions or a poor driving environment. For example, if you drive in deep sand, you may face the severe effect of overheating. This can cause excessive wheel slip. Once the AWD system has overheated, you’ll receive a caution message on the information display. In the process, you may notice the AWD light go off and on at will. 

How to Fix?

The thing to do once you observe the warning message of an overheated AWD system is to pull over. Park your vehicle and allow the engine to cool down for at least 15 minutes. The warning message will most likely turn off once the AWD and engine have cooled off. The normal AWD system will start working and the light to start working normally.   

Other things to look out for as possible of illuminating service AWD light include the defective differential clutch and loose cap gap. 


What does AWD fault service required to mean?

Anytime you receive this warning message on your AWD information display, it means that the service AWD system isn’t working properly. Hence, it may need to fix it. The message often displays alongside the transmission, throttle, or AWD indicator light. You may need to consult your auto technician or any professional mechanic for a proper diagnosis and a quick fix.  

Can you drive with the AWD light on?

Yes, you can drive with the AWD light on. However, a problem begins if the indicator light illuminates even after you switched off your car engine. Normally, when the engine goes off, the AWD light is supposed to follow suit. Any abnormality or malfunction in the AWD system will cause the light to stay on even after you’ve turned off the car.   

Final Thoughts

What does it profit you as a car owner if you can’t take every sign on your vehicle seriously? Consistency with regular routine auto maintenance will prevent a lot of issues relating to the AWD system. When next you observe the AWD warning light come on permanently, it’s time to get to the action. I hope this article helps. Drive safely!