What is wrong? if the service vehicle soon light comes on?

It means your vehicle's onboard computer system has self-diagnosed some kind of problem.
use maxiscan us703 clear the fault codes.

u have to get it scanned and cleared at a shop

your vehicle has two lights..one is a service engine soon and the other is a service vehicle soon,if the S.V.S light is on..its most likely an abs problem and it needs to be scanned or your alternator might not be charging and the system voltage is a little too low for some things to operate correctly,either way the car needs to be scanned and/or have the charging system checked,hope this helps

I am assuming its not the service engine soon light it is probably the service vehicle soon light, There are 2 lights service vehicle soon upper left side, and service engine soon upper right side.

When all these come on at the same time it is the wheel bearing sensor. Usually the wheel bearing needs to be replaced which houses the sensor. A sure way to check is to press your sls button by your shifter and see if the light goes out, If it does not, u will need to have a wheel bearing put in.

take the vehicle to the dealer. ths is what the owners manual would tell you to do for the check engine light.

The service light means something is wrong with the car and it needs attention now. Get the codes checked and that will tell you what is wrong with it.

The reason for the light to come on an the after you have switched the vehicle off and back on again and the engine light stays dead is because the control units of the vehicle will reset when the ignition is switched off for 10sec. If the light stays off the it might be that the car got a wrong reading from a sensor and caused the engine light to come on. If it was a serious problem the light would have come on again

You'll need to know why the service engine light comes on, they can check this by using a OBD II diagnostic tool to find the trouble code stored in the pcm, ask them to run a check on it, or you can take it to a mechanic before you buy it to have them check over the vehicle for any minor or major problems.

Your vehicle is sensing some sort of non-engine fault. In most cases, I have found it to be a burned up light bulb.

99 - 04 grand am.

I had the "service vehicle soon" light come twice with in 1 year. First the heald light bulbs were gone. Replaced the head light bulbs and after 2 starts the "service vehicle soon" light was gone.

The second time the DRL - #194 amber bulbs were gone. Replaced these and the "service vehicle soon" light was gone after 2 starts. The DRLs are housed in the headlamp housing, the tiny bulbs beside the head light.