How to Replace the Knock Sensor on a 2005 Ford Five Hundred

The knock sensor is one of the many electronic advancements made in the automotive industry since government regulations began restricting vehicle emissions. This sensor detects the knock created by the detonation of the air-fuel mixture in the combustion chamber. If the knock is too intense, it sends a signal to the powertrain control module to retard the ignition timing until the excessive knock goes away. This component plays a key role in the Five Hundred being able to run on regular 87-octane gasoline. Without this sensor instructing the computer to retard the timing, 87-octane fuel might cause an audible knocking noise from the engine, and a failed knock sensor could result in this symptom. Replacing the 2005 Five Hundreds knock sensor is a straightforward task, once you know where Ford mounted it.

Instructions

1

Loosen the pinch bolt on the negative battery cable, using a combination wrench, and pull the negative cable off the battery.

2

Wedge wheel chocks under the backside of the rear wheels. Raise the front of the Five Hundred with a floor jack and slide jack stands under the vehicles subframe. Lower the Ford onto the jack stands.

3

Crawl beneath the vehicle so that you are under the drivers side of the engine and find the knock sensor connected to the engine block, just before the engine and transmission connect. The sensor has a rubber heat shield around it to protect it.

4

Pull the heat shield away from the sensor. Press and hold the unlocking button on the knock sensors wiring harness and unplug the harness. Remove the knock sensor retaining bolt with a ratchet and socket and remove the knock sensor.

5

Position a new knock sensor on the engine block and hand-thread its retaining bolt. Tighten the knock sensor retaining bolt to 15 foot-pounds with a torque wrench and socket. Plug the wiring harness into the receptacle on the new knock sensor.

6

Pull the heat shield over the knock sensor.

7

Raise the Five Hundred off the jack stands with a floor jack and remove the jack stands. Lower the vehicle to the ground.

8

Reconnect the negative battery cable and tighten the cables pinch bolt with a combination wrench.