The camshaft position sensor does pretty much what its name implies – it senses the exact position of the rotating camshaft and it provides that data to the PCM. From there, that information is used, along with data from the crankshaft position sensor, to manage ignition and injector timing. In addition to that, on modern vehicles with variable valve timing, there is a mechanism on one or more camshafts that advances the timing; the camshaft position sensor on those vehicles also monitors the VVT system operation. There is usually one sensor for each camshaft.
The sensor itself is built simply; its main functional part is a coil of fine wire in a housing that creates a magnetic field. This will sit very close to the tone ring attached to the camshaft. The tone ring spins with the camshaft and has notches or teeth formed in it that allow a varying signal as the spinning disc disturbs the sensor’s magnetic field. The result is a signal which the PCM uses to see the position of the camshaft.
Usually, the camshaft position sensor is on the top of the engine, plugged into the valve cover or the cylinder head, and is fairly easy to access and replace.
Cost of Camshaft Position Sensor Replacement
On average, for most vehicles, it costs about £110 to replace a camshaft position sensor.
For some specific examples of common vehicles, using £70 to £100 an hour as a labour rate:
- For a 2010 Nissan Altima with a 2.5-liter engine, the labour to replace the cam position sensor is 0.4 of an hour. A factory sensor lists for £80, and an aftermarket part costs about £55. This makes the job about £110 using original parts, or about £80 using aftermarket parts.
- For a 2008 Toyota Camry with a 2.4-liter engine, the labour time to replace the cam sensor is 0.5 of an hour. A factory sensor lists for around £60, and a non-OEM component costs about £50. This makes the job about £95 using factory parts, or about £85 using aftermarket parts.
- For a 2014 Jeep Grand Cherokee with a 3.6-liter engine, the labour time to replace a cam sensor is 0.6 of an hour. A factory sensor lists for £40, and a non-OEM part costs about £25. This makes the job about £80 using factory parts, or about £65 using aftermarket parts.
What Else can Cause a Camshaft Position Sensor Code
In most cases, there would be a standard hour of diagnostic charges added to the above estimates. But it’s also common enough to just replace the sensor based on a trouble code.
If a vehicle shows up with an engine light for camshaft position problems, there are just a couple of simple things to rule out, and ordinarily the sensor is replaced. For a more involved diagnosis, it’s a good idea to take a look at the waveform of the sensor signal with an oscilloscope to get an idea of how well it is working, but most shops don’t have an oscilloscope set up for that, and the cost of replacing the part is relatively small.
This can lead to a situation where the sensor has been replaced, but the code comes back because the sensor was reading accurately and wasn’t actually the problem. Often the code is for a cam/crank correlation error. That means that the readings of the crank sensor and the cam sensor aren’t in agreement, which usually means that the timing chain or belt has worn or stretched. It can also sometimes mean that the variable valve timing system is malfunctioning. Both of those can be much more expensive and time consuming to diagnose and repair, so often it’s still reasonable to try the easy thing first – replace the cam sensor.
FAQ
Usually yes. The primary signal the engine needs to run is the crank sensor. The cam position sensor is secondary and most engines can run without it, though some will go into “limp mode” with limited power and reduced performance.
Usually yes; most of the time, the sensor is easily accessed and only held down by one bolt. On most engines, there is either no calibration needed or it is done automatically.
Most mechanics would say yes, it’s a good idea to avoid problems. But it’s also easy enough to replace the sensor, and there’s always a warranty on that kind of part. If a new sensor works right out of the box, OE or aftermarket, it will likely continue to work fine indefinitely.