Look inside the trunk. Should have a sticker on the left trunk arm.
inside the car
Code p0430
look on the trunk hinge there should be a sticker with the code on it
You won't know until you get the code read.
You will find a sticker in the trunck with the factory code printed on it.
retrieve key less entry code for mercury marquis
The door code for 2000 Mercury Grans Marquis is usually factory programmed into the keypad. <><><> In SOME cases, the factory door code is printed on a sticker placed on one of the hinges of the trunk lid. Take a look and see.
p1131 = lack of HO2S11 switches - sensor indicates lean
Trouble code P0125 means:Insufficent coolant temperature for closed loop fuel control
You cannot reprogram it. A dealer can get you the Master Code if you've lost it.
Mine was under the trunk lid. When you open the trunk you can see it up underneath towards the back. A white sticker with 5 black numbers on it. '94 Grand Marquis
You cannot change the master code. You can add other codes, but you cannot change the master....