What does service engine soon mean on a 2002 Altima 3.5S?

The service engine soon light on a 2002 Altima 3.5SE means you need to have some sensors replaced. Depending on when your car was built, it may have 2 or 3 recalls. The major recalls are for a crank shaft sensor and two cam shaft sensors. You wouldn't expect a 'service engine light' to trip on a 2002 model, but this is common to new model year vehicles. The light on my '02 Altima 3.5SE went on last week with only 28k miles. The dealer replaced the sensors and found the light was tripped more than likely from the cam shaft sensors, since a problem with the crank shaft sensor should normally prevent your engine form starting. Get this recall/warranty service done soon. I noticed poor gas mileage and slower acceleration. Cam sensor could cause slight misfires which could bring up your fuel consuption. Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. There are "monitors" or self test the computer runs the car through, if a problem occurs, it may not run all of the self tests until that problem is taken care. Therefore, another problem may exist.