xtriggerman
Well-Known LVC Member
If you are not familiar with this check engine code on your MK, I just had it. With just over 90K on the car, I thought I would get a new speed sensor since that is what the P0500 code refers to and as I ordered a new Motorcraft sensor at Rock Auto, the Cart came up with a needed "sensor plug connector". OK, seems they knew something I'v yet to know about this sensor issue. Sure enough, the pig tail coming out of the sensor on the car were free of any insulator coverings and touching. The Sensor its self is located in the tail shaft housing of the trans, on the left side. The new connector had the 2 pig tail wires as white so it didn't need to be spliced in to either specific color wire on the car harness. The big problem was getting to the loom to cut it all open so I could cut out the burned up connector wires back to the point where they were still in rubber insulator coverings. This entailed disconnecting the trans shift cable from its position on the trans housing and dropping the left side exhaust pipe. This allowed me to see the speed sensor wires actual come out of the big black connector plug thats pined into the trans mount cross member and not coming out of the main harness bundle as the loom covering would lead you to believe. Freeing up that big black plug and those sensor wires was the only way to get at the good portion of wire to solder the new pig tails into them. As you can see, the sensor must generate enough heat to turn the insulation rubber into dry chalk that promptly falls away at the slightest movement. I hope this is a good heads up to those that might be under there doing other work. Take my advice and at very least, buy a new sensor plug connector and solder it in while your under there. Wish I knew about this issue when I did the dual exhaust mod 
