VDC Light-Cause and Fixes

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 It is a big advantage knowing the related meaning behind your vehicle’s dashboard warning lights. It also doesn’t hurt knowing how to fix some of the underlying issues that are causing, for instance, your VDC light to illuminate. 

The VDC dashboard light comes on when your vehicle’s stability control system is disengaged. The term, Vehicle Dynamic Control (VDC) is primarily used in Nissan vehicles in reference to its traction control system.

Sharing a similar function to a traction control system, the VDC system allows drivers to maintain control of their cars in slippery driving conditions. It does this by reducing engine speeds and either applying brake pressure to the slipping wheel(s) or increasing power to the wheels to steady your vehicle.

Usually, the VDC light can be cleared by turning your car on and off. If your VDC light is still on afterward, you will need to have a thorough diagnostic inspection carried out to identify and fix the issue. However, a flashing VDC light is normal and usually means that the system is actively working to maintain the stability of the vehicle.

What causes the VDC Light to illuminate?

Bad wheel speed sensors

There are wheel speeds sensors (WSS) mounted on each of your wheels. Their function is to monitor the rotational speed of your wheels and relay this information to your vehicles’ Electronic Control Unit (ECU).

The ECU uses this information to determine when to activate your vehicle’s stability system. Due to their location on the wheel, it is not uncommon for the WSS to get damaged or dirty, which compromises their ability to send actionable information to the ECU.

In some instances, your WSS gets severed by road debris; you can verify this upon inspection by looking for exposed copper wire. Despite the cause of damage, your vehicles onboard computer will always respond by disengaging the car’s stability control system.

The VDC light will come on, as a result, to communicate the presence of a fault in one or more components within the stability control system. You can fix this and clear the VDC light by either cleaning your WSS or having them replaced by a professional.

Faulty alternator

The function of your vehicle’s alternator is to recharge the car battery. A defective alternator cannot effectively recharge your car battery, and this, in turn, affects electrically powered components such as the VDC system.

The insufficient supply of power causes the system to disengage and the dashboard light to illuminate. As far as factors that are causing your VDC light to turn on, a faulty alternator is easy to diagnose.

This is because there will be other accompanying symptoms such as dim lights, and the battery warning light will turn on as well. The only way to fix a faulty alternator is to replace it with a new one. However, your mechanic should first inspect the entire charging system to rule out loose or corroded battery cables before replacing the alternator.

Bad steering angle sensor

The Steering Angle Sensor (SAS) plays a significant role in your vehicle’s electronic stability program. It monitors steering wheel actions and relays this information to your vehicle’s ECU.

If the steering angle sensor is damaged or faulty, it will send false messages to your vehicle’s control unit throwing the stability control system out of whack. Your vehicle will be unable to respond to any input or action provided to the steering wheel as it normally would.

For instance, turning your steering wheel right will not result in a reciprocated action by your vehicle. This can cause your VDC dashboard to illuminate. To remedy this, your mechanic can either reset or recalibrate your steering angle sensor.

Low levels of brake fluid

As mentioned earlier, your VDC system will apply brake pressure to slipping wheels to help maintain control of the vehicle. Low brake fluid can lead to brake failure, which will ultimately affect VDC function.

It is therefore very possible that this could be the reason why your VDC light stays on. Luckily, topping up your master cylinder reservoir should clear your VDC light; if this doesn’t work, you may need to check for worn-out brake pads and have them replaced.

Damaged hydraulic circuits

Every vehicle has a dual hydraulic system that works as a failsafe should the main brake line fail. This safety measure activates a second set of brakes allowing the car to stop even if the main brake line fails.

The ECU will turn the VDC light on the moment it detects damage to the hydraulic system circuits. You will need to have the damaged circuits replaced to turn off the VDC light.

Improper wheel alignment

Steering your vehicle should be effortless, misaligned wheels make it difficult to drive in a straight line. Additionally, your tires will wear out unevenly, and this can result in loss of traction and hydraulic pressure to one side of the vehicle.

This can lead to brake failure, especially at high speeds, which can pose a significant danger to you and other motorists. Wheel alignment is essential and plays a vital role in your vehicle’s stability control. Misaligned wheels can cause the VDC light to illuminate and can easily be fixed by having them properly aligned.

Damaged stator ring

The stator ring and the wheel speed sensor both relay information about rotational speed to the ECU. You see, the stator ring is a notched magnetic ring; when it rotates, its teeth activate the magnet in the sensor, creating a magnetic field.

The magnetic field then generates an alternating current that is carried to the ECU. The ECU determines whether the voltage (signal) received matches the manufacturer’s specification of a functioning wheel sensor.

A damaged stator ring will disrupt this process and produce a lower output voltage that will cause the ECU to turn on the VDC light. To diagnose this issue, your mechanic will need to inspect the stator rings for rust or missing teeth manually. Damaged stator rings cannot be repaired and will have to be replaced.

Faulty ABS module

Your vehicle ABS module regulates the amount of brake pressure applied individually to each wheel. Depending on the manufacturer of your vehicle, the ABS control module is either located in the engine bay or the frame rail on the driver’s side.

ABS modules that are located in the engine bay get exposed to extremely high temperatures when the engine is running and cold temperatures when the vehicle is off. Sometimes the repetitive exposure to different temperatures damages the circuit board.

This can be very dangerous as it may cause the ABS module to misinterpret the speed signals it receives from the WSS and apply the brakes at the wrong time.

It is not advisable to attempt to fix this issue yourself, as this can result in costly repairs. It is better to take your vehicle to a professional where a thorough diagnostic test can be carried out to determine whether it’s a damaged circuit board or a cracked solder joint.

In conclusion

Your vehicle’s stability control system is an important safety feature that should always be in good working condition. Without it, you will be left defenseless in adverse weather conditions.

As mentioned earlier, your vehicles ECU disengages the entire stability control system when a faulty component is detected. It is therefore highly recommended that you take your car to a professional mechanic the moment any of your stability control system-related warning lights illuminate.

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Steven Reilly
Steven Reilly is a qualified mechanic and his passion for cars goes beyond just the technical aspects. He is also an amateur racer and all round car enthusiast. When he is not driving them, he can often be found in his garage under the hood of a rare model. Steven Reilly has lost track of the number of hours he has spent setting up his fine collection of rebuilt models. He believes that cars can provide a constructive and fun opportunity to teach the youth important life skills. In line with this, he is developing a community outreach program, potentially dubbed ‘Cars for change'.

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