Sometimes when i start the car it has no power, the check engine light is on, the reduce power light is on, and the traction control light comes on for no reason. what could be wrong

Hook up a professional grade scan tool to the vehicles computers an check for DTC'S diagnostic trouble codes , that will tell a professional mechanic what to check.

With some makes and models this is normal. The PCM will reduce engine power when the traction control senses wheel slip as a safety precaution until traction is restored

the "Reduced Engine Power", problem causes the PCM to disable "Service Stability Control" and "Traction Control" turning on the warning lights to come on for those systems . The reduced engine power is because of a problem with the electronic throttle control system or as GM calls it TAC system . Reduced Engine Power Mode
When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The PCM will continue to use the accelerator pedal for throttle control, however, the vehicle acceleration is limited.
• Limited throttle mode--The PCM will continue to use the accelerator pedal for throttle control, however, the maximum throttle opening is limited.
• Throttle default mode--The PCM will turn OFF the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The PCM will perform the following actions:
- Limit engine speed to idle by positioning the TP, or by controlling the fuel and spark if the throttle is turned OFF.
- Ignore the accelerator pedal input.
• Engine shutdown mode--The PCM will disable fuel and de-energize the throttle actuator.
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Drive by Wire training Your best bet , take it to a GM dealer

Since all three systems work together, when the engine light is on the other two can be also.
I would start with checking the engine computer for trouble codes.

Engine power reduced problem is the main culprit ! This has to do with the electronic throttle control system . Computer controlled throttle control . The Gas pedal assembly has position sensors as does the throttle body . These are inputs to the PCM/ECM - engine computer . By the signal from the gas pedal the PCM / ECM will control a DC electric motor on the throttle body ,opening an closing the throttle plate .When there is a problem with this system the check engine light comes on and the PCM/ECM will disable traction control an that light will be turned on etc..... These problems can be very tough to find . How much are you willing to spend to track down this problem . Need special tool's to find these problems . Electrical test scope (lab scope ) . Over time these parts wear an the PCM will see conflicting signals . Sometimes the part needs to wear out to find the problem . Have the repair shop keep the vehicle till they find the problem .
Throttle Actuator Control System

Drive by Wire Function and diagnostics by Wells

Reduced power is a problem with electronic throttle contol . drive by wire . Do you know what this is ? Taking the vehicle an having it hooked up to diagnostic tool an checking for DTC'S - diagnostic trouble codes is always a first step when trying to find the root cause of any trouble light ! And not auto zone , pep boys , or advance auto parts . Thier diagnostic tool will not check codes in all system control modules .

Hi there?
The traction system is linked to the engine managment, if there a fault in the traction system it can reduce the engine power output. You need to scan the traction control system to see what fault code comes up.

It means the traction control system has been disabled. It can be done manually by pressing the switch on the dash or by an onboard computer (meaning there is a problem). If you can't press the button to get the light off, then get it scanned. Traction control system works with the anti-lock braking system and the engine to help the driver control the vehicle in the event it should be slipping or skidding. It will activate the anti-lock brakes, help reduce steering pressure to better steer and can sometimes cut out engine cylinders to reduce the power going to the wheels to better control in the skid.

Hello Jeremy.
When your traction light comes on it is indicating wheel spin on acceleration. To prevent wheel spin an onboard computer reduces engine power to limit the wheel spin. Some, if not most, cars equipped with this feature will also apply the brakes if wheel spin continues after reducing engine power.
Hope this answers your question.
Thank you for using Fixya!

It sounds like these things are all related. When the a computer sees a problem in the Electronic throttle system, it will dissable traction control, and give the reduced engine power alert because the powertrain computer does not know the value of throttle postion.
Codes will need to be scanned in the computersto begin diagnosis.
TechJK