There is no factory code on Lincoln vehicles. A 2003 Lincoln LS code is either committed to memory, or it can be found on the wallet card which comes with the car when it is purchased.
Actually I am looking for the same thing. I used to work for Ford around the time these cars where out. The codes were usually on one of trunk hindges. My is not there but I am curious if yours is.
It's in the trunk, next to the air ride shut off switch, has the factory code right on it. Actually, the code in located on the Computer Module.
( 5W-20 ) according to the 2005 Lincoln LS Owner Guide
According to the 2005 Lincoln LS Owner Guide : The 5R55S automatic transmission does not have a dipstick
Trouble code P1904 means: Kickdown Solenoid Circuit High Voltage
All Lincoln LS transmissions are sealed. There is no dipstick to check fluid.
108
2005
locate he computer module on lincoln ls 2004
in the truck by the spare tire compartment
In the trunk next to the spare tires.