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Ron Z.
Ron Z., - Toyota Tech -
Category: Toyota
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Experience:  18+yrs experience. State Inspector and Toyota Diagnostics
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What causes a VSC light to come on?

Resolved Question:

The trac off and the VSC warning light, along with the check engine all came on at once while driving. The car still operates well. What is likely the cause? This is an ‘05 Scion XB.

Submitted: 5 years ago.
Category: Toyota
Expert:  Ron Z. replied 5 years ago.

Welcome to JustAnswer! I will do my best to answer all of your questions completely and accurately.

When the Check Engine light comes on, the VSC/Trac light(s) are also set, which turns these systems off. This is a self-preservation mechanism, in case the reason the Check Engine Light is on can harm or effect the VSC/Trac systems. So- fix the reason why the Engine Light is on, and the VSC/Trac system(s) will come back online.

When the Check Engine light comes on, this is the on-board computer's way of telling you it sees a problem in one of the monitored systems. Unfortunately, there are literally 100's of parts and sensors monitored in various systems, and to take a "guess" as to which part/sensor in which system is faulty, is virtually impossible. However, if you are not experiencing any drivability issues such as skipping, stalling, shifting problems, etc., then more than likely, the problem is going to lie in the EVAP (emissions) system. Very commonly, this could be a faulty, loose or missing fuel cap or even putting fuel in while the vehicle is running. Check the cap for any cracks in the rubber O-ring on the underside. Check the fuel filler neck for any signs of chips or debris. Check under the vehicle, around the area of the fuel tank and the EVAP canister looking for any vacuum lines that have dry-rot cracks, holes or loose/missing connections. If these all check out, then the best thing to do at this point is to have the "p-codes" read from the on-board computer. These p-codes are what is used as a "starting point" for the diagnosis and will tell which part/sensor in which system has the fault. There isn't a Mechanic on the planet that can tell you what is wrong with the vehicle just by "looking" at the Engine Light.

Every single Mechanic's first course of action WILL be to obtain the p-codes. Once you get these p-codes you can more accurately and efficiently diagnose the problem and then make the repair. You can have these p-codes read FREE (except in California) at any local "big chain" part store (ie. AutoZone, PepBoys, Advanced, etc.). If you still need help after retrieving the codes, you can bring them here, and any of our Techs can walk you through the diagnostic procedure, and then even help you make the repair if you feel confident enough to try.

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VSC light explained

Vehicle Stability Control (VSC) is a feature found on Toyota vehicles designed to help reduce accidents by assisting drivers to control horizontal slides. Designed in 1995, VSC has been added to many Toyota made vehicles to stop wheels from slipping and losing traction. VSC works by lowering the power of the engine and forcing the brakes to be applied to the wheels. When VSC is activated, it controls the stability and allows the vehicle to go back into a stable situation. This has allowed Toyota to lower the risk of accidents.

Car driving in the rain

What causes a VSC light to come on?

Often when the VSC light appears, there could be an issue with the system installed. However, the VSC light could come on when the ABS, check engine or traction control light comes on, or when the wheel speed sensor has gone out. If the VSC light does come on, it is recommended to use a scan tool to find the error code and help diagnose the problem.

First, ensure the gas cap is tight. Some models of Toyotas will flash the check engine light and VSC light simultaneously if the gas cap is loose. Turn your engine off, tighten the gas cap to at least one click, and try the engine again.

How to reset a VSC light

When the VSC light does come on, and it is just a malfunction, there are ways this can be reset.

  1. Turn off the vehicle and apply the parking brake, so it does not move while working on it.
  2. Raise the car hood and remove the negative battery cable for a few minutes. By disconnecting this battery cable, this should allow the vehicle's internal computer to reset and reset the VSC light.
  3. Start the vehicle, and if the light does not appear, then everything should be okay. However, if the light comes back on, there could be a problem. In this case, the car will need to have a scan tool ran to see to determine the faulty codes.