My check transmission light came on in my 2004 mercury sable driving at 75 mpr for 35 min, the air conditioner on; it shifted ruff. I stared the car later the message wasn't on, what could it be?

SOURCE: 1999 Ford Taurus Wagon stays in 1st gear

Most Ford Taurus wagons have a transmission that generally goes first. that's the main reason. Just something to do with the way they are built. The only advice that I could offer is either replace the tranny or just not run the a/c. Usually it's just the motor working twice as hard running the a/c and that in turn puts the computer into the phase of lower gears for the transmission. there in being the problem.

SOURCE: 2000 Mercury Sable double overhead cam Transmission problem

manual para reparación cadena de tiempo de motor v6 3.0 sable 2000

SOURCE: Check charging system icon keeps coming on

I had the same problem with a 99 sable and it was the drive belt

SOURCE: 98 mercury sable

See my answer to post by dwood1542 on 2/6/09 for 1998 Taurus. It could be the VSS (Vehicle Speed Sensor). The same thing happened on my 1998. The VSS drives the speedometer and tells the electronic transmission how fast the car is going. So, if you are moving and it happens, look at your speedometer. If the speedometer goes to zero, its the VSS. P500 and P502 codes may be stored in OBD-II.

SOURCE: Air bag light on 2000 Mercury Sable

it can be two things the gas is low in the air bag or the sensor itself inside the front bumper is sticking