Top 5 Bad Camshaft Position Sensor Symptoms

There are a lot of things that can go wrong in your vehicle if you have a bad camshaft position sensor. You will know when these problems present themselves because the symptoms will become very apparent.

Below are five common signs which will indicate a faulty camshaft position sensor.

1) Ignition Issues

The mixture of air and fuel in the internal combus

The mixture of air and fuel in the internal combustion engine requires a spark in order for the ignition to take place. In certain vehicles, the spark cannot be generated if there is a bad or faulty camshaft position sensor.

If you cannot generate a spark, then you cannot start your engine. You might not immediately assume the camshaft position sensor is to blame for an engine that won’t start. But if you take your vehicle to a repair shop, do not be surprised if the mechanic tells you that the camshaft position sensor is to blame.

2) Difficulty Shifting

If you are driving an automatic transmission vehic

If you are driving an automatic transmission vehicle and your camshaft position sensor goes bad, you can expect your set gear to lock in place. This means that you will have trouble shifting to another gear, although you might not be able to shift at all.

The only thing that you’ll be able to do is to turn off your car, wait a few seconds, and then turn it on again. This is just a temporary solution so that you can get your vehicle to the nearest mechanic quickly.

If you don’t replace your camshaft position sensor, the shifting problem will come back for sure.

3) Poor Engine Performance

A faulty camshaft position sensor will cause an im

A faulty camshaft position sensor will cause an improper amount of fuel to be injected into the cylinder chamber. The engine will not respond very well to this because it depends on a proper mixture of air and fuel to function adequately.

When you step on the gas pedal to accelerate, you will notice weaker performance. You won’t be able to go faster than 30 to 40 miles per hour in many cases. Not only will you fail to go faster, the vehicle may start to stutter and jerk around as well.

4) Low Fuel Efficiency

The fuel injectors will possibly be putting too mu

The fuel injectors will possibly be putting too much fuel into your cylinder chamber if you have a bad camshaft position sensor. As more fuel gets used up, this will create a problem for the fuel efficiency of your vehicle.

You will notice that your gas mileage is reduced and that you’ll be pumping gas more frequently.

5) Check Engine Warning Light

The camshaft position sensor is a component inside

The camshaft position sensor is a component inside the engine. If this sensor were to malfunction or go bad, it will cause a chain reaction that will affect other functions of the engine.

It should be no surprise that the “Check Engine” warning light will illuminate on the dashboard if this happens.

Of course, this light could illuminate due to any number of problems inside the engine besides a bad camshaft position sensor. But if you experience at least a few of the other symptoms that were mentioned above, then you can assume there is a problem with the camshaft position sensor.

No Injector Pulse

One of the operational objectives of the camshaft position sensor is to regulate the amount of fuel that goes into each cylinder. The position of the camshaft helps the engine control unit determine the timing as well as the duration of every fuel injection.

In some cases when the ECU observes a breakage in transmission from a failing camshaft sensor or a complete shut-off, it can disable the fuel system. That means the fuel injectors will have no pulse when firing causing the vehicle to not start.



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How to Replace a Camshaft Position Sensor

  1. Disconnect the negative battery cable.
  2. Locate the sensor. It’s usually on the top, front, or rear part of the engine. It will likely have a 2-3 wire connector attached.
  3. Release the tab on the sensor to disconnect the wires from the sensor.
  4. Remove the mounting bolt which attaches the sensor to the engine. It’s usually an 8mm or 10mm bolt.
  5. Pull the sensor off with a slight twist.
  6. Apply a bit of engine oil to the o-ring of the new senor.
  7. Install the new camshaft position sensor and secure with the mounting bolt.
  8. Reconnect the wire connector to the sensor.
  9. Reconnect the negative battery terminal.


When you bring your vehicle in to a dealership or repair shop for routing service or a tune-up, the mechanic won’t normally inspect the camshaft position sensor if they are not asked to.

If you have experienced any of the warning signs listed above, let them know you think it may be the camshaft position sensor. This will allow them to quickly inspect the camshaft position sensor to determine whether it’s causing these problems.

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Can You Drive With A Bad Camshaft Position Sensor?

On some vehicles, a bad crankshaft position sensor can create a no-start condition while for others it may trigger limp mode. Driving itself can become cumbersome with a bad camshaft position sensor, so it’s best to replace it. Though if you are able to drive the car without much problem, you should still get your car scanned for trouble codes. A bad camshaft sensor is bound to trip a check engine light.

I. A Camshaft Position Sensor Can Fail Without Warning

An intermittent or complete CMP sensor failure while on the road could be dangerous. It could happen at any time: You are driving on the highway, moving along in fast traffic, when your engine suddenly loses power. There is nothing to do but watch in horror as a vehicle approaching at 70 miles an hour rear-ends you. Not a pretty picture, but it's happened many times.

Other times the driver becomes aware of a failed CMP sensor when the engine refuses to start.

Here, we'll explore the symptoms of a bad camshaft position sensor and what you can do about it. But let's discuss first what the sensor does.

Camshaft position sensor location

The camshaft position sensor is always located near the camshaft, often at the top of the valve cover, but it can also be installed from the side of the cylinder head.

Check around the head or valve cover and follow any electrical wires and you will for sure find the camshaft position sensor.

What to do after replacing the camshaft sensor?

The first thing you have to do after replacing the camshaft sensor (or fixing any car issue) is to use the OBD scan tool to erase the associated trouble codes. You may also opt to drive the vehicle for about 10 minutes so that the check engine light can turn off automatically indicating the issue has been fixed. 

Replacement Cost For A Camshaft Position Sensor

If it turns out that your camshaft position sensor

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.

Symptoms Of A Bad Camshaft Position Sensor

As a camshaft position sensor plays an important r

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

The most common symptom of a bad camshaft position

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.

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

A more serious but thankfully rarer symptom is whe

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.

Unable To Start The Car

This symptom is related to the previous one. As th

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

When everything is as it should be, a nice and ste

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.

Camshaft Position Sensor Replacement Cost

Looking for Replacement Parts?We recommend Parts Geek for the best prices and selection.

Out of all the sensors in your vehicle, a camshaft

Out of all the sensors in your vehicle, a camshaft position sensor is often one of the least expensive. Depending on your make and model, expect to pay between $20 to $100 in most cases for a replacement sensor.

On top of that, add about $60 to $90 in labor costs. Altogether, you’re looking at a total between $80 and $190 (+ tax) to replace your camshaft position sensor. If you’re having the replacement performed at a dealership or you drive certain luxury or performance vehicles, plan on spending more.

Fortunately, those with even a bit of mechanical experience can often replace the sensor on their own with the help of a repair manual or YouTube video specific to your vehicle. In many cases the location of the sensor is easy to get to but in others, it can be a real pain.


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