The camshaft position (CMP) sensor is just one of many electrical parts found in a vehicle. We’ll go over what’s in this component, the symptoms of a bad camshaft position sensor, and what you can expect for its replacement cost when it’s defective.
Many people confuse the camshaft position sensor with the crankshaft position sensor because they sound similar. But there is a big difference between the two, as they perform different functions in the vehicle and show different signals when something goes wrong.
Related: Single Overhead Cam Engine vs. Double Overhead Cam Engine
What is a camshaft position sensor?
All modern vehicles are equipped with a camshaft position sensor. This sensor is a very important part of any vehicle, as it helps ensure that the engine is running properly.
You may have trouble seeing the sensor when you look under the hood of your car. Different car manufacturers usually have their own unique location near the engine to mount the sensor. You can find it on the back of the cylinder head, in the vehicle’s tappet valley, or near the engine block.
The purpose of a camshaft position sensor is to determine the position of the camshaft relative to the crankshaft. This data is then sent to the powertrain control module (PCM) for use with fuel injection and/or ignition system control.
Common Symptoms of a Bad Camshaft Position Sensor
#1: Check Engine Light Comes On
When the camshaft position sensor is faulty or starts to have problems, the first thing you should notice is the “Check Engine” light that comes on on the dashboard. Of course, the “Check Engine” light could indicate a variety of problems and not necessarily a bad camshaft position sensor.
In this case, you should use an OBD2 scan tool to find the diagnostic trouble codes stored in your car or have a professional mechanic inspect your vehicle’s engine control module to see what is wrong. They will also scan this module for a series of error codes that will tell them what the problem is.
Do not delay or postpone scanning or inspecting your vehicle when the Check Engine Light comes on, or your engine could be seriously damaged. The engine may even fail, meaning you will have to rebuild or replace your engine.
Related: Code P0010, Code P0011, Code P0013, Code P0016, Code P0340, Code P0341, Code P1345
#2 – Ignition problems
When the camshaft position sensor starts to have problems and becomes weak, the signal to the car’s computer also becomes weak. This means that the signal is eventually so weak that it will not allow the car to start because there will be no spark in the ignition.
#3 – Car vibrator or smell
If you are driving your vehicle and the camshaft position sensor starts to fail, sometimes the engine will lose power and cause your car to jerk or shake randomly.
These are a result of the incorrect amount of fuel being injected into the cylinders, as the PCM receives incorrect information from the camshaft position sensor.
#4 – Engine stall
Even worse than not being able to start your car is having your engine stall or stall while driving because the fuel injectors are not being told to inject fuel into the engine cylinders.
We probably don’t need to tell you how dangerous this situation could be.
#5 – Bad acceleration
Adding to the bricks, your vehicle will not be able to accelerate very quickly when your camshaft sensor starts to fail. Heck, you’d be lucky to go over 30 miles per hour in some cases. Acceleration is again poor due to poor fuel delivery through the injectors.
#6 – Travel problems
Some car models with a faulty camshaft position sensor will have a stuck transmission that sticks in gear. The only way to get out of this speed is to stop the engine, wait a bit, and restart.
This is only a temporary solution, and the problem will occur again, so a sensor replacement is needed as a permanent solution.
Additionally, your vehicle may go into “limp mode,” which will not allow you to shift gears or accelerate above a certain speed.
#7 – Bad fuel mileage
Not supplying enough fuel to the engine is the opposite. In this case, due to an inaccurate reading from a faulty camshaft position sensor, more fuel than necessary is injected into the engine, causing fuel consumption to decrease.
Camshaft Position Sensor Replacement Cost
To replace the camshaft position sensor, you can expect to pay between $95 and $200. The parts alone will cost between $25 and $100. Labor costs will range from $70 to $100 for a professional replacement.
Expect to pay more if you have a luxury vehicle or if your local car dealer makes the replacement car. Additional fees and taxes will also be added to those costs.
Can you replace the camshaft position sensor yourself?
Yes. It’s one of those jobs that almost anyone can do and is an easy way to save the minimal labor cost (often close to $100) that a repair shop or dealer will charge you. Replacing it should take 5 to 10 minutes.
How to replace the camshaft position sensor
- Disconnect the negative battery cable.
- Locate the sensor. It is usually located on the top, front, or rear of the engine. A 2- or 3-wire connector is probably connected.
- Release the sensor tab to disconnect the sensor cables.
- Remove the mounting bolt holding the sensor to the engine. This is usually an 8mm or 10mm bolt.
- Remove the sensor with a small twist.
- Apply some engine oil to the O-ring of the new sensor.
- Install the new camshaft position sensor and secure it with the mounting bolt.
- Reconnect the cable connector to the sensor.
- Reconnect the negative battery terminal.
When you take your vehicle to a dealership or repair shop for a break-in service or tune-up, the mechanic generally will not inspect the camshaft position sensor unless instructed to do so.
If you have encountered any of the warning signs listed above, let them know that you suspect it could be the camshaft position sensor. This will allow them to quickly inspect the camshaft position sensor to determine if it is causing these problems.