Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost


How can you tell if your car has a bad camshaft position sensor? This guide shows you all the symptoms and what the expected replacement cost is. The camshaft is a very important component of a car’s engine. Its main task is to operate the intake and exhaust valves. It may also drive other components such as the fuel pump, oil pump, and power steering pump.

Given that the camshaft is in charge of perhaps the most important task in the car, which is determining the intake and exhaust rate, many symptoms may appear if something is defective. It can be a bit tricky to distinguish the camshaft from the crankshaft, not only due to their similar names but also because they work together. The camshaft is connected to the crankshaft by a timing belt or timing chain. This is important as the crankshaft also determines the positioning of the pistons, synchronizing the entire process.

If the camshaft position sensor is faulty, the synchronous process may be disrupted, causing multiple symptoms. In this guide, we will cover everything you need to know about a bad camshaft position sensor, including the replacement cost and diagnostics. Let’s get started!

What Is A Camshaft Position Sensor?

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

Just as the crankshaft works together with the camshaft, so do their respective sensors. The camshaft position sensor sends information to the engine control unit which in turn uses that information to power the engine.

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The engine control unit and camshaft, together with its sensor, ensure that the appropriate amount of fuel and air is added to the combustion chamber and that it ignites at exactly the right moment. If it turns out that the camshaft is not functioning properly, your car could have problems starting, accelerating, or stalling.

Symptoms Of A Bad Camshaft Position Sensor

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

As a camshaft position sensor plays an important role, many issues can arise if it is bad. The most common symptoms that occur are the following:

  • Check engine light
  • Stalled engine
  • Unable to start the car
  • Rough idle
  • Reduced engine power
  • Bad gas mileage

All these symptoms may appear individually or together. In most cases, the check engine light will illuminate alongside one or more of the symptoms. In the text below, each of the symptoms listed will be explained so you can get a clearer picture of the problem affecting the camshaft position sensor.

Check Engine Light

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

The most common symptom of a bad camshaft position sensor is the appearance of a check engine light. As always, when the light comes on, it will probably be unclear what the problem is. In order to get a clearer picture, you should scan your car for any error codes with an OBD2 scanner.

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If you do not have an OBD2 scanner, you should take your car to a mechanic. If you can avoid it, you should not drive your car if the light illuminates, as more damage could be done. If you know the cause of the check engine light, you might be able to drive the car to the shop, provided that a professional mechanic or someone equally qualified has given you the green light.

In many cases, the so-called “limp mode” might engage. This is a safety feature that restricts the power and speed of your car to protect all its components. Generally, you can drive your car to the nearest shop if the limp mode is engaged. Just like the check engine light, the limp mode might disappear when you turn your engine off and on again.

Stalled Engine

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

A more serious but thankfully rarer symptom is when the engine stalls. This could happen when you are in a parking spot or when you are driving on the road. The latter scenario can be extremely dangerous. If your engine stalls unexpectedly, do not drive the car at all. This problem is caused when no combustion occurs as no fuel or air enters the combustion chamber at the right moment.

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Unable To Start The Car

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

This symptom is related to the previous one. As the sensor does not work optimally, the engine will have a hard time starting. As with almost any other symptom, this could be due to a variety of reasons. Other reasons why a car won’t start might be due to a faulty starter, clogged fuel filter, dead battery, or other reasons.

Rough Idle

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

When everything is as it should be, a nice and steady idle will largely go unnoticed by the driver. However, when the idle is rough, it will be very noticeable while driving. If the camshaft position sensor is faulty, the rough idle is due to the unsynchronous combustion taking place in the cylinders.

A rough idle might also be a consequence of a faulty fuel pump or EGR valve. Whatever the cause, it is important to know what causes the rough idle. It may require some extra tools and testing to find out.

Reduced Engine Power

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

Reduced engine power comes in two forms. Either the reduced power is due to the limp mode, as a precaution, or no message or light in the dashboard is seen, and the car moves roughly. You may notice the reduced engine power when accelerating or simply a drop in engine speed when coasting or idling. It may also present itself as vibrations when accelerating. All of this is due to ineffective combustion and misfires occurring in the cylinders of the engine.

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Bad Gas Mileage

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

As the camshaft sensor provides inaccurate information to the engine control unit, an abnormal amount of fuel may be injected into the combustion chamber. Not only will more fuel be injected, but the combustion will also occur at a sub-optimal time, leading to more unburnt fuel, and in turn a bad gas mileage. This symptom can be harder to notice as it happens over a prolonged period. You will also need to be aware of the usual fuel mileage of your car.

Replacement Cost For A Camshaft Position Sensor

Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

If it turns out that your camshaft position sensor is bad, you will need to replace it with a new one. If you are experienced with working on your car, you could even do it yourself! Changing the sensor is not very hard, but it might be in a position that is difficult to reach. This means you might need some patience to replace it.

In terms of buying a new sensor, it will cost, on average, $90 to $140. The labor cost should set you back $70 to $100. As with any other replacement, the cost is affected by the type of car as well as the repair shop. Premium brands and dealerships are almost always more expensive. Either way, expect to pay a total of $160 to $240 for a camshaft position sensor replacement.

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Symptoms Of A Bad Camshaft Position Sensor And Replacement Cost

The camshaft position sensor is small but very important for your car’s engine. It ensures that fuel and air combust at the appropriate time in the combustion chamber of the engine. It works closely with the crankshaft as well as the engine control unit. If the sensor does not work properly, many symptoms may arise.

Usually, a check engine light will turn on. Other symptoms include bad gas mileage, rough idle, engine stalling, and engine power loss. Each of the symptoms might be hard to differentiate. In most cases, it is best to leave your car with a professional mechanic and let them fix the problem.

A broken camshaft position sensor has to be replaced and will set you back a total of $160 to $240. The price depends on what car you drive as well as the repair shop that completes the work. If you have the necessary tools and patience, you could also change the sensor yourself. In that case, the only thing you would need to do is buy a new sensor, which should cost between $90 and $140.

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