Question

P1126 2001 Nissan Altima:
Service engine soon dash light comes on after 20 to 30 minutes of drive time.
Is P1126 thermostat related or throttle control motor relay related? Both descriptions show up on different scanners

Answer 1

P1126 for this car is for the cooling system.

check for leaks, if none are found replace the thermostat but I would suggest you replace the coolant temp sensor also due to the age of the car.