In the late 1970s and 1980s, crank shaft position sensors were introduced on some very early motors, particularly on some GM vehicles. It was a very slow sensor in a way, and it only had maybe 12 to 16 teeth on the electric wheel. It was used primarily to time the ignition and control the ignition. For this, they were using a coil pack for the first application, but as vehicles evolved, the cranking shaft position sensor has too. On modern vehicles, you may see up to 92 windows on a electric wheel for a crankshaft position sensor. This may seem like a lot, but it’s tracking an awful lot, and it’s able to sense a whole lot more than what they did in the beginning. With this, they’re able to see small pulses inside the engine. In other words, when that cylinder fires, reaches the top of the stroke, starts to go back down, it can be seen with a crank shaft position sensor. This information is used for a lot of different functions on the engine, transmission, and even the body.

I know we’ve covered misfire detection, but remember, the high resolution from this sensor can detect those small changes in movement of the crank shaft that is changed by what’s going inside the combustion chamber. This is critical, especially if you’re operating variable valve timing and other emissions components. Also, a crank shaft position sensor is used in stop start vehicles. You may not realize this, but the starter engages on some of these vehicles around 250 RPMs as it shuts down the engine. By knowing that exact RPM and the position of the engine, it can engage the starter and then use the direct fuel injection and other components on the engine to start it up quicker at a light.

So make sure when you’re installing one of these or replacing one of these, confirm that it’s bad. Also, make sure that you’re programming the crankshaft position sensor. Different vehicles have different procedures. It could be going in and holding the RPMs at 2,000 RPMs while you’re sitting it with the scan tool. Some vehicles you may have to drive for a while. Just make sure you’re doing this to prevent future codes from coming back on the vehicle. I’m Andrew Markel, thank you very much.

This video is sponsored by Auto Value and Bumper to Bumper.