My trac off and check engine lights on how do I reset the computer or disable trac sys

Is your trac light lit ? If so it has a problem an till it is fixed , you can't reset it. Need to have it checked for DTC'S - diagnostic trouble codes .
If the ABS control module detects a malfunction, it will disable TCS and will command the BCM to turn the TRAC LED Off. The driver can also disable TCS, if desired, by depressing the TRAC switch. When the driver depresses the TRAC switch, the ABS control module will disable TCS and will command the BCM to turn the TRAC LED Off.
DTC C0276 TCM Traction Control Not Allowed
DTC C0275 or C0276
The TCM sends a serial data message to the electronic brake control module (EBCM) indicating that torque reduction is temporarily not allowed.
DTC C0550
DTC C0896
The electronic brake control module (EBCM) is required to operate within a specified range of voltage to function properly. During antilock brake system (ABS) and traction control system (TCS) operation, there are current requirements that will cause the voltage to drop. Because of this, voltage is monitored out of ABS/TCS control to indicate a good charging system condition, and also during ABS/TCS control when voltage may drop significantly. The EBCM also monitors for high voltage conditions which could damage the EBCM.

No, your check trac light is used to monitor the traction control system. It is sensing an issue in the traction control system, which is pretty complex. There may be a code saved in the computer that a dealer could pull for you.

The traction control system uses the engine to slow down or speed up the car when necessary.
If the check engine light is on the traction control will not work.
You may have a problem with both systems, but having the computers scanned for trouble codes will point you in the right direction.

Your vehicle is equipped with 4 of them. They are located at each of the 4 wheels. There are other reasons that the Traction Control light can come on...wheel speeds sensors are not the only reason, athough they are the most common. The traction control system works with the engine/powertrain control system and with the antilock brake system. A bad wheel speed sensor will usually also turn on the Antilock Brake (ABS) light. If the Check Engine light is also on, you could have an engine control problem causing the Trac light to come on.
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If the Trac light is on by itself, you may just have the traction control turned off. The Trac Off switch is located on the steering column.

If none of the above solves your problem, then you will have to scan your computer system to find out why the light is on. ( i.e. failed wheel speed sensor...but which one?)

It means you turned off the traction or pushed the ETS button on the gear shift.

The Enhanced Traction System is an all-speed engine based traction control system used by General Motors Corporation in many of their models. In some models, the driver has the option to disable this system by pushing a button marked "ETS". The system uses sensors to monitor wheelspin and reduces engine speed, upshifts or retards ignition timing to improve traction

When the computer detects certain faults it will set the check engine light on along with the other lights you've explained. I've seen this on many toyota SUV's. Usually the codes set are oxygen sensor related. There really is no relation between the oxygen sensors and the traction control system but for some reason it disables it and sets the warning lights on. Have the computer scanned for codes at a shop or at a parts store such as autozone for free.

TCS stands for Traction Control System.
The traction control system works in conjunction with your Antilock Brake System (ABS) and your Engine Control Module (ECM) or Powertrain Control Module (PCM) or Electronic Control Unit (ECU) (Note that ECM, ECU, and PCM all mean the computer that controls your engine, depending on make.)

Anyway, the traction control system can apply one or more of the brakes and control engine RPM in the event that a wheel slip has been detected by the traction control system.

Pushing the TCS button on most models will light a lamp in the instrument cluster that usually says "Trac Off" Pressing it a second time will turn this light back off.

When the "Trac Off" light is illuminated, the Traction Control System is disabled and will not work in the event of a wheel slip.

Also note that when the Traction Control System is working and a wheel slip is detected, The Traction Control Module will usually illuminate a light that says "Trac" as it is taking control of your brakes and engine. It can feel really strange when this occurs and some people think that their transmission is slipping or that their engine has a misfire problem.
The chances are that if it occurred on wet, slippery pavement, the Traction Control System may have just saved your life.

If this is happening on dry pavement and normal driving conditions (starting, stopping, or turning), there may be a problem with the system. "False Traction Control" can happen just like a bad wheel sensor causing "False Antilock Mode".

Also check your Owners Manual for more specific information pertaining to your particular vehicle.

how do I determine which oxygen sensor is bad on my 2003 forerunner ? the check engine light is on and also the vsc trac

Sometimes it's a complaint with the ABS braking system. If it comes on and you have no other problems and stays on for while, check your brakes. I have had this issue before and had my brakes replaced. They were worn but for some reason were not squeaking.