Do you own an all-wheel drive (AWD) vehicle? Well, AWD system is a common term in the automotive industry. It improves a vehicle’s traction and performance in challenging conditions. Thus, once my friend asked, “Why did my all-wheel drive turn off?” So, I will answer the reasons for this issue of AWD in this blog.
AWD distributes power to all four wheels of a vehicle.Sometimes, the engine shuts off unexpectedly while you are on the road. Thus, several reasons arebehind this problem. But I am giving you a glimpse of those reasons right now.
Any AWD vehicle can turn off due to electrical defects in the ignition system, fuel delivery, battery, and charging. It may also stop working because of sensor failure. Again, if the vehicle fails to control the traction, it may suddenly shut off. Other reasons are software or programming glitches, mechanical failures, and irregular maintenance.
Symptoms of AWD Problems & Sudden Turn-Off of the Engine
Assume your all-wheel drive car has shown any symptoms below while driving. Then, consider the vehicle is about to get further issues, including turning off without warning.
Warning Messages on the Dashboard
Before you have the issue of turning off, you may get warning messages on the vehicle’s dashboard. They can be different depending on the vehicle brands and models. Some of them can be like “Service Rear Axle” or a “Malfunction in the All-Wheel Drive System” warning (sources: 1, 2, 3).
Check Engine Light
I hope you have heard about the malfunctioning indicator lamp (MIL). It is commonly known as the check engine light, a part of OBD II (source). Hence, this light may illuminate when you have problems with the AWD system. But you can resolve them by retrieving the trouble codes using a code scanner (source).
Grinding Noise at Highway Speeds
You may hear unusual grinding or whining noises from the AWD system.You may listen to those noises when you are at highway speeds. These noises may indicate AWD system parts issues, like the transfer case or differential (source).
Blinking Lights in the Drive Selector
Your car may have selectable drive modes or AWD settings with indicator lights. These lights can blink when any problem appears in the system. So, blinking lights is another sign that you may need to treat quickly to avoid sudden turn off (source).
Other Signs
A faulty all-wheel drive system can disable traction control andABS. It may also cause vibrations while driving (source). Other symptoms includetrouble shifting gears and issues with AWD engagement and disengagement.
Impact of All-Wheel Drive Turning Off
If the AWD turns off, you can witness significant changes in your car’s performance and safety.
On Vehicle Performance
Using the all-wheel drive system, you can distribute power evenly to all four wheels evenly. It is more beneficial on slippery or uneven surfaces.
But when your AWD turns suddenly, the vehicle wheels cannot get power evenly. Eventually, it causes decreased traction, particularly when you drive on snow, ice, or mud (source).
The vehicle may behave differently than expected with AWD turned off. As a result, you may not handle the vehicle adequately. It makes driving risky, particularly at higher speeds or when taking turns.
On Safety
AWD system provides additional traction and stability while driving the car. But when it is turned off, it will increase the risk of accidents. You may get bad vehicle control in weather conditions like rain or snow (source).
Some vehicles have selectable modes you can switch on when needed. For example, when the AWD mode turns off, it may turn on the two-wheel drive (2WD) mode (source). But only the front wheels are used for steering and propulsion in 2WD mode. It will reduce your control over the car.
Common Reasons for AWD System Disengagement or Turn-Off
If you cannot decode the symptoms, you should learn why all-wheel drive turns off. In this part, I will discuss the reasons for the sudden AWD turn-off.
Malfunctioning Transfer Case Control Module (TCCM)
Sounds technical, right? The TCCM is responsible for overseeing the operation of the AWD system.If it fails, it can trigger warning lights and affect the functionality of the AWD system (source). Usually, TCCM becomes non-functional due to electrical and mechanical faults with transfer cases or sensors.
Traction Control and Stability Control Interactions
Traction control and stability control systems can override AWD’s operation. They work to improve vehicle stability and traction in various driving conditions.However, some situations likeaggressive acceleration, cornering, or loss of traction may cause these systems to disengage the AWD system. But it’s for all your safety! Particularly when you drive on snowy or wet roads, you can regain stability (source).
Defective Transfer Case
As I already said, the transfer case is essential to the AWD system. When this transfer case gets mechanical faults, it may turn off the all-wheel drive system. However, you will hear grinding, clicking noises, or difficulty while shifting into a 4-wheel drive with a defective transfer case (source). It may also cause the vehicle not moving at all.
Sensor or Electrical Issues
The AWD system depends on the sensor feedback while the vehicle is on and moving. So, the sensor or electrical problems can affect all-wheel drive functionality. For instance,a slipping all-wheel-drive oil pump for low oil can cause the AWD system to become disabled. If it happens, you may get codes like C0407 or a “service rear axle” message on the dashboard (source).
Bad switch
Any issue with the front axle engagement switch can cause a malfunction in the AWD system. But how will you know about a bad switch? Well, you will have difficulty engaging the drive system(source).
Low oil
Did you check the oil level? After all, low oil in an AWDaffects its performance and components. For example, it causes problems with the transfer case. And problems with the transfer case can cause trouble to thetransmission’s ability to shift gears (source). Low oil can cause more problems like the rear differential clutch control module will store a code and disabling AWD (source).
Overheating or Overloading
Do you often put excessive loads on the AWD vehicle? Suppose you have aggressive driving habits, tow heavy loads, or drive under extreme conditions. Then, an overheating problem will appear, and turn off the system without warning. It may prevent further damage to the system (source).
Mechanical Failures
Mechanical failures in components like the rear differential, driveshaft, or axle shafts are also the reasons to turn off the all-wheel drive. Wear and tear, the needof maintenance, or other issues may cause mechanical failures. Suppose your AWD car turns off due to mechanical issues. In that case, you may get symptoms like unusual noises, vibrations, or unmanageable systems.
Loose Gas Cap
A loose gas cap can cause the all-wheel drive system to turn off.If the gas cap is not tightened up properly, it may trigger a check engine light. As a result, it will cause a malfunction in the AWD system (source). Additionally, a loose gas cap can allow contaminants into the fuel tank. It may eventually cause engine misfires (source).
How to Troubleshoot All-wheel Drive Turn-Off Problems
You can follow these steps to troubleshoot AWD problems:
- Check for warning messages on the dashboard, such as “Service Rear Axle” or “Service Engine Soon”.
- Look for symptoms like grinding noise at highway speeds, blinking lights in the drive selector, or difficulty staying in AWD or 4WD.
- Check the transfer case control module, vacuum system, oil levels, gas cap, and wires for any defects or malfunctions.
- If the oil level is low, properly fill the oil reservoir and tighten the gas cap.
- Inspect and maintain the battery and electrical components of the vehicle regularly. It willmake sure the proper functioning of the all-wheel drive system.
- Try disconnecting and reconnecting the battery or pressing the brake pedal down as you switch different modes to reset the system.
Suppose the above solutions do not solve the all-wheel drive turning-off problem. Then, my suggestion is to visit a trusted automobile repair shop to diagnose or fix your vehicle properly.
Final Words
“Why did my all-wheel drive turn off?” – I hope you have understood the reasons properly. Inspect every component properly if your vehicle is stopped due to AWD issues.
Follow the instructions I have mentioned earlier. Hopefully, you can solve the problem soon. Still, you may contact a professional mechanic if you cannot identify what happened.
Thanks for reading this blog. Have a safe driving!
