Most fuel-injected vehicles use a crankshaft sensor, which sends a signal to the computer to determine the crankshaft's position. The computer uses the signal for engine speed and shift points. Often, vehicles use the crankshaft sensor in conjunction with one or more camshaft sensors. The camshaft sensors also send a signal to the computer, which the computer uses to determine a combination of engine speed, top dead center of the No. 1 cylinder, shift points, and, depending on the vehicle's engine management system, cruise control. If the crank sensor malfunctions, the car will not start and must be replaced.
Locate the crankshaft sensor for your particular vehicle. You can find the location by referring to the owner's manual for your vehicle. You might find the crankshaft sensor behind the crankshaft pulley or under the intake manifold, depending on the year, make and model of your vehicle. Some auto parts stores also offer a service for their customers in which they will look up locations or repair instructions.
Remove any component in the way of gaining access to the crankshaft sensor. It is usually located on the front of the vehicle, behind the crankshaft pulley. On some vehicles, it is located underneath the intake manifold, in which case the intake must be removed.
Unplug the crankshaft sensor's wiring harness connector by spreading the tangs on the side of the plug and pulling the plug off of the sensor.
Remove the retaining bolt or bolts holding the sensor on the block with the appropriate socket. Most sensors use one or two bolts. Pull the sensor off of the block.
Install the new sensor and tighten the retaining bolt or bolts firmly. Do not over-tighten the bolts as you will damage the sensor. Plug in the wiring harness connector, ensuring that it snaps into place and that the tangs fit over the plug so that the plug cannot come off of the sensor. Reinstall any components that had to be removed to access the sensor.
