Is It Safe to Drive With a Bad Camshaft Sensor? What You Need to Know

How does camshaft position sensor work?

The camshaft position sensor identifies camshaft r

The camshaft position sensor identifies camshaft rotation by using its sensor’s magnet. The movement of the rotor affects the direction of the magnetic field radiated by the magnet in line with the position of the detection tooth position. This occurs as the detection tooth, linked to the timing rotor, moves to and fro the camshaft position sensor.

Consequently, the MRE (magnetic resistance element) value changes, and the engine’s ECU voltage is applied to the camshaft position sensor. At the same time, the difference in MRE resistance value is reflected as an alteration in the voltage.

Along the line, the waveforms of the MREs outputs experience varied amplification and take a rectangular waveform that is affected by a circuit located in the sensor. The processed MRE outputs or voltage is relayed to the engine’s ECU.

How Does a Camshaft Position Sensor Work?

Now that you have a better idea of what a camshaft position sensor is, we want to talk a little more about how it works when you have your car turned on. It should help to give you a better understanding of why it’s so important to have a fully-functioning camshaft position sensor in your car. It’ll also shed some light on why you need to know how to check if a camshaft position sensor is bad.

This is the process that plays out when it comes to your car’s camshaft position sensor:

  1. The camshaft in your car’s engine spins when you have it turned on
  2. The camshaft position sensor keeps a close eye on the camshaft to see how quickly it’s spinning
  3. The camshaft position sensor lets your car’s engine control module know how quickly the camshaft is spinning
  4. The engine control module compares the information it receives from the camshaft position sensor with the information it receives from the crankshaft position sensor
  5. The engine control module adjusts your car’s fuel injection based on the info it receives from both the camshaft and crankshaft position sensors

This process might seem simple enough. But it takes place over and over and over again while you have your car running. This pushes your camshaft position sensor to the limit by forcing it to work almost all the time, which can eventually cause it to wear down. As a result, you need to be aware of how to check if a camshaft position sensor is bad so that you can replace it as needed.


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. 

Is the Cost of a Camshaft Position Sensor Worth It?

Are you planning on keeping your current car and driving it around for at least several more years? If so, then you’re going to find that camshaft position sensor replacement will be well worth the costs associated with it. For under $250 in most cases, you can have a brand-new camshaft position sensor put into position so that you can be sure it’s able to carry out its job from now on.

The only time you might not want to pay the price to have camshaft position sensor replacement done is when you have a very old car with other engine issues. You should still know how to check if a camshaft position sensor is bad in an old car. But if you discover that it does, in fact, have a bad camshaft position sensor, selling your car rather than replacing the camshaft position sensor might be your best option.

How to replace camshaft position sensor

Step 1: Remove the harness wires

Step 2: Remove the camshaft sensor with a 10 mm wrench. Check for chips and damaged cam sprockets.

Step 3: Insert new camshaft sensor

Step 4: Replace harness

How to Remove and Replace a Camshaft Position Sensor.

5. Engine Stall

If the ECU can’t keep track of the timing sequence of the engine, then this can cause the engine to cut out. In this case, a stalled engine can be caused by a lack of fuel but more often than not, it’s actually an intentional shut down to protect the engine from damage. If the ECU detects a problem with the camshaft sensor circuitry, then it may cut out the engine, or stop it from starting.

III. How the Sensor Can Fail

Just like every part or component in your car, the CMP sensor will eventually stop working when it's reached the end of its service life, because an internal part, wire, or related component has failed. The symptoms your engine may experience at this point can vary, depending on the type of sensor failure: for example, a problem in the circuit, the connector, the sensor itself, or a related component.

Once your car's computer detects a CMP sensor failure, it will trigger the engine light and store a diagnostic trouble code (DTC) in its memory (see the table below for common camshaft position sensor trouble diagnostic codes).

1. Check Engine Light on the dashboard

A broken camshaft position sensor is going to impact the timing of the engine, especially the fuel delivery timing. If the ECU stops receiving a signal from the camshaft sensor, then this indicates a problem with the sensor or some other part of the camshaft sensor circuit.

This will cause the check engine light to flash or

This will cause the check engine light to flash or stay on. If the sensor is still sending a signal to the ECU, then chances are the check engine light won’t come on, and it may indicate a problem with another part of the engine such as the ignition coils or spark plugs.

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What Are the Symptoms of a Bad or Failing Camshaft Position Sensor?

1. Check Engine Light Comes On

The most common indicator that the camshaft position sensor is failing is a lit Check Engine light.

OBD II (on-board diagnostics II) systems efficiently monitor vehicle hardware and software and can detect part deterioration that causes imperceptible performance changes before a part completely fails. Although you can connect to the ECM using a DIY scan tool to try and diagnose the problem, it’s best to take it to the pros when the Check Engine light illuminates. Ignoring the Check Engine light can lead to expensive engine or transmission repairs.

2. Poor Drivability

A failing camshaft position sensor begins losing its ability to quickly transfer data. Mismatched fuel delivery and ignition timing, even if off by a few milliseconds, will cause your vehicle to sputter, accelerate poorly, lack power, stall or even shut off.

3. Transmission Shifting Problems

Data received by the ECM from a failing camshaft position sensor can keep transmission shift solenoids from operating and gears from shifting. Called “limp-home-mode” on some models, it helps protect the engine from damage by restricting engine speed.

4. Bad Fuel Economy

Inaccurate camshaft position sensor data can keep fuel injectors open too long, forcing excess fuel into the combustion chamber. This also can cause engine knocking and serious damage if too much liquid gasoline (which does not compress) builds up in the combustion chamber.

VIII. What If My CMP Sensor Seems to Be Working Fine?

If it seems your CMP sensor is working correctly, consider these possibilities.

Fuel injectors not firing:

In many vehicle models, the car computer uses the CMP sensor signal to fire the fuel injectors.

If you've determined that your engine has spark but fuel injectors are not firing, there's a chance your CMP sensor has failed.

CMP Sensor internal circuit malfunction:

It's not uncommon for a CMP sensor's internal circuitry to develop an electrical open. This is usually caused by the sensor being exposed to engine high operating temperatures.

High temperatures can break a wire. The broken wire may still make contact while the engine is cool. As soon as the engine compartment temperature increases, the damaged wire may expand and separate, creating an intermittent failure.

Faulty timing belt or chain:

If your tests seem inconclusive, especially if the problem has triggered a CMP sensor-related trouble code, you may want to check your timing belt or chain.

Timing belts (not so much timing chains) will stretch after miles of hard work, and tensioners will wear out over time, upsetting spark timing.

This will not only show the symptoms of a bad camshaft sensor but even trigger a CMP sensor-related trouble code.

Some car manufacturers suggest replacing a timing belt and tensioner every five years for this reason.

If necessary, consult the vehicle repair manual for your particular vehicle make and model.

Common Symptoms of a Faulty Camshaft Position Sensor

#2 – Ignition Problems

As a camshaft position sensor starts having proble

As a camshaft position sensor starts having problems and weakens, the transmitted signal to the car’s computer weakens as well. This means the eventually the signal is so weak that it will not allow the car to start since there will be no spark from the ignition.

#3 – Car Jerking or Surging

If you are driving your vehicle and the camshaft p

If you are driving your vehicle and the camshaft position sensor starts failing, the engine will at times simply lose power and cause your car to jerk or randomly surge forward.

These are both a result of an improper amount of fuel being injected into the cylinders since the PCM is getting incorrect information from the camshaft position sensor.

#4 – Engine Stalling

An even worse scenario than not being able to star

An even worse scenario than not being able to start your car is that your engine actually shuts off or stalls while you’re driving because the fuel injectors aren’t being told to inject fuel into the engine cylinders.

We probably don’t need to tell you how dangerous that situation could be.

#5 – Poor Acceleration

Aside from jerking, your vehicle won’t be able to

Aside from jerking, your vehicle won’t be able to accelerate very fast when your camshaft sensor begins to fail. Heck, you’d be lucky to accelerate past 30 miles-per-hour in some cases. The poor acceleration is again due to incorrect fuel delivery by the injectors.

#6 – Problems Shifting 

Certain models of cars with a bad camshaft positio

Certain models of cars with a bad camshaft position sensor will end up with a locked transmission that stays stuck in a single gear. The only way you’ll be able to get out of that gear is to shut off your engine, wait a bit, and then restart.

This is only a temporary solution and the problem will reappear so replacement of the sensor is necessary as a permanent fix.

Along with this, your vehicle may put itself into “limp mode” which won’t allow you to shift gears or accelerate beyond a certain speed.

#7 – Bad Fuel Mileage

This is the opposite of not delivering enough fuel

This is the opposite of not delivering enough fuel to the engine. In this case, because of an inaccurate reading from a bad camshaft position sensor, more fuel than necessary is injected into the engine which causes your fuel economy to drop.

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.



#1. Check Engine Light – The first most common sign of a failing camshaft position sensor is a check engine light coming on the dash. That is because the car’s computer is pretty smart in its own right of figuring out if something is not working right or not.

If you get a check engine light you should use an OBD2 code reader to find out why. If you don’t have one, then an auto shop will normally read the code for you. Once you have the code you have to figure out what it means.

If the code is for the camshaft position sensor, then you know that it is bad or going bad. If a check engine light comes on it is important to have the codes read as soon as possible. That is because damage can happen to the engine the longer you let the problem go on. You should use best obd2 scanner to find the code.

#2. Ignition Problems – If you don’t get a check engine light, then the next most common sign of a camshaft position sensor going bad is ignition problems. That is because the sensor is giving the computer the wrong information and it is releasing the gas into the wrong cylinders. Another possible issue is that the wrong spark plugs are sparking. If you have trouble starting your car and know that the battery is good, then you should check the position sensor to make sure it is working right.

#3. Car Jerking or Stalling – If the sensor starts to go out in the middle of driving, then you might not get a check engine light right away. That is because some computers only check certain parts when starting the car. A way you can know that it is going out while driving the car though is you will start to feel jerks or lurches. That is because the engine will lose power or the improper amount of fuel will be injected. This means that if you start noticing your car driving poorly, you might want to pull into somewhere to get it checked out.

On top of this though your car might not jerk but instead stall. This means that it will just stop running right where it is at. This is really bad because it can lead to wrecks or getting rear-ended. The reason why the car might stall is that the computer might not be being told to inject fuel into the cylinders at all. If your car stalls put on your hazards, and try to start it back up so you can move it off the road. If it won’t start up and the road is not busy put it in neutral and push it to the side. Once out of the way you will have to get your vehicle towed to a shop to get looked at.

#4. Poor Acceleration and Trouble Shifting – Another way to notice if the car is reading the wrong camshaft position is poor acceleration. You won’t be able to get up to speed very quickly because the wrong cylinders will be getting the fuel or spark. In some cases, the car might only be able to get up to a certain speed. That is because the engine is not putting out its full power. If your car won’t go the speed it normally can, then something is wrong and it is important to have it checked out. Another reason why your car might not be accelerating right is it might be locked into one gear. Some vehicles if the camshaft position sensor gets out of wack will not be able to change gears. This means you will be stuck in first or low gear and cars are not designed to drive quickly in this year.

#5. Bad Fuel Mileage – The last sign of something being wrong is bad fuel mileage. If your car manages to run relatively normal to you and you drive it a bit, then your fuel mileage will still be severely reduced. That is because a lot of extra fuel is going into the wrong cylinders. On top of all this when the cylinder with the extra fuel does spark, it will cause a large explosion in the cylinder causing major wear on the engine. Even if your car can drive with a bad camshaft position sensor you shouldn’t because it is not efficient and it causes major wear and tear on your engine.

Camshaft Position sensor replacement cost

The average camshaft position sensor replacement cost is between $100 and $250. The part itself costs between $75 and $120, while labor costs range from $30 to $130.

A little market research will help you get the best price for the part and the associated labor costs.

On average, this part is not very expensive, and the cost of replacing a camshaft position sensor is between $75 and $120 for most vehicles. These prices can vary depending on which supplier you buy it from, where you live, and which company makes it. The cost of replacement in a luxury car can be relatively much higher. If you don’t replace the camshaft position sensor yourself, the labor cost of replacement would be an additional $30 to $130, depending on which car dealer you get it repaired by. If you were to replace it yourself, the cost of replacement would be nearly halved. It can be easily replaced using the tools you most likely already have.


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