Service engine light on 2003 pontiac montana disconnect

Check the wheel speed sensors. Traction control reads wheel speeds to know when a tire loses traction(it speeds up compared to the others). When the TC control module(computer) senses a problem such as a sensor out of tolerance, or an open circuit, such as a broken or disconnected wire/connector, it disables the TC and lights the light as a tell-tale.
Are you having trouble with ABS? Usually a wheel speed sensor defect will also affect the ABS too.

That sensor is in the exhaust system near or on the catalytic converter under the car.

PUT A BREAKER BAR ON ENGINE CRANKSHAFT BOLT AND SEE IF YOU CAN GET THE ENGINE TO TURN OVER BY HAND,IF IT WONT TURN, SOUNDS LIKE SOMEONE SOLD YOU A EHICLE WITH A LOCKED UP ENGINE. GOOD LUCK!!!!1

maybe just temporary--but usually means 02 sensor conditions or vacuum leak--get car scanned with a tech ll

did you try to reset oil life system to see if light goes out at next
start up if it does your system was not reset properly at yuor last oil change

I would suspect a vacuum leak. it is uncommon that a fuel pump would set a code like this..

please re post codes as they are not manufacturers codes ,4 numbers only

I would disconnect the battery minus - cable first, ensure the airbag connectors are the same ! otherwise I do not think you have a problem !!

have it scan.sound like mass air flow sensor problems

you need to put it on a computer to find what the code is such as on o2 sensor or a number of other things. once you know the codes you can fix the problem