camshaft position sensors

Camshaft Position Sensor Symptoms, Function & Location

In Engine by Magnus Sellén9 Comments

Since the engine uses the readings from both the crankshaft and camshaft sensors, a malfunction of either sensor could affect the readings and performance of your engine.

The camshaft sensor is always operational when you are driving the car or the engine is running. For this reason, the camshaft sensor can become poor over time. The ring gear may also wear out and interfere with the readings.

Camshaft position sensor information

camshaft position sensor

Apart from the drive, the camshaft can also become defective in the event of an accident or if water enters your car, as it is both an electronic and a mechanical component. There can be a number of other reasons for a defective camshaft. Mechanical damage to the sensor or wires can cause it to lag or fail completely. Internal short circuits can cause the camshaft sensor chips to go bad. It may also fail due to the breakage of the encoder wheel. Otherwise, problems may occur if the connection between the sensor and the control unit is accidentally broken.

The camshaft position sensor is a crucial part of the engine management system that ensures that the engine runs smoothly. The sensor is responsible for collecting information about the camshaft speed of the vehicle and sending it to the engine management system (ECM). This data is used to determine the ignition timing and fuel injection timing.

If the camshaft sensor fails, the engine suffers and there are problems with acceleration, fuel efficiency, ignition problems and more. In this article, we’ll look at some common symptoms that will help you determine if your vehicle’s camshaft sensor has failed or is defective.

Camshaft Position Sensor Symptoms

The camshaft position sensor can be damaged over time by an accident or regular wear and tear. Sometimes it is also damaged by oil leaks. Here are some of the symptoms that will help you determine whether or not your camshaft position sensor is damaged.

The most common symptoms of a bad camshaft sensor are hard starting conditions and reduced engine performance is likely. A bad camshaft sensor can put the engine into a limp mode, i.e. a state in which you have limited functions for your engine. Here are some descriptions of the most common symptoms.

Problem Symptoms Causes Solutions
Bad camshaft position sensor Hard starting condition/Long cranking time

Reduced engine performance

Check engine light

Hard shifting condition
Faulty wirings to camshaft position sensor

Corrosion in connector to sensor

Faulty camshaft position sensor

Faulty ECM(Rare)
Repair wirings to sensor

Clean connector to sensor

Replace camshaft position sensor

Replace ECM/PCM (Rare)
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1. Poor Engine Performance

One of the most common problems that occur due to a poor camshaft position sensor is that the power of the engine drops dramatically. You will notice frequent stalling, idling and a drop in engine speed. Fuel efficiency also decreases. All these problems should be addressed immediately and they usually occur because of a damaged camshaft position sensor.

2. Poor Acceleration

In addition to engine vibrations and stalling, a poor camshaft sensor also leads to a significant reduction in acceleration. If you cannot drive more than 35 miles per hour, this is most likely due to a defective camshaft sensor.

3. Problems with Shifting Gears

In some cars with automatic transmission, the transmission is blocked and gets stuck in a single gear due to a damaged camshaft position sensor. To change gear, the driver has to stop the engine, change gear, and start the engine again. This is far from ideal, and is a sign of a damaged camshaft sensor.

4. Engine Won’t Start

As the camshaft sensor becomes weaker, it does not send the signal to the on-board computer and as a result the ignition system cannot produce a spark. No spark means that the engine will not start at all, indicating that the camshaft sensor has failed completely.

5. Check Engine Engine Light Comes On

The check engine light illuminates for many reasons, including when the camshaft position sensor fails. If the check engine light on your car lights up, it is recommended that you visit a car specialist and have your car scanned to check the fault code. People usually ignore the “check engine” light without knowing that this could be a sign of something serious, including engine damage.

What is a Camshaft Position Sensor?

The core functionality of the camshaft sensor is to work in combination with the crankshaft sensor of your vehicle. Its purpose is to determine the position of the crankshaft drive very precisely. As a result, it generates the signals in the same way as the crankshaft position sensor. It helps the engine to determine the exact time the first cylinder is in the top dead center position.

camshaft position sensor location

The information generated by the camshaft is used by the engine system for various purposes. Essentially, the information helps to start the injection process during sequential injection. It also supports the actuation signal for the pump nozzle injection system and calibrates the knock control.

The Hall principle is the core working concept of a camshaft sensor. A ring gear on the camshaft is scanned and the rotation of the ring gear causes a change in the voltage of the Hall IC located in the sensor head. This induces a change in the voltage transmission of the control unit. The information resulting from the change is read electronically and evaluated by the computerized system to record the data. In other words, a bad camshaft can also interfere with the functionality of the crankshaft position sensor, and ultimately it will cause various problems for the overall experience you have with your vehicle in terms of engine performance.

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Where is the Camshaft Position Sensor located?

camshaft position sensor location 2

In most vehicles, the camshaft sensor is usually mounted on the engine block or on the cylinder head of the engine. The position of the camshaft sensor can vary depending on the engine model and manufacturer. Use the service manual of your car to locate it if you cannot find it.

Testing a Bad Camshaft Position Sensor

Step 1: Locate the Sensor

In order to test the camshaft sensor, we need to apply a number of techniques to verify that it works. The first step is to locate and remove the camshaft sensor. The camshaft sensor is located near the crankshaft and is positioned above the cylinder head of the engine. Since the sensor is easily accessible and no other part needs to be removed to reach it, installing a new sensor is also easy.

Step 2: Unscrew Bolts and Plugs

As soon as the old camshaft position sensor is located, you must remove it. The sensor is fixed by means of bolts and plugs which can be removed with a socket wrench. Since the sensor is connected to the ignition system by cables, these cables must also be removed. Finally, remove the sensor from the casing.

Step 3: Use Multimeter to Test the Sensor

To test the camshaft position sensor, you need a multimeter and a magnet. Connect the sensor to a multimeter and set it to diode or low resistance function. Use the magnet and move it several times in front of the sensor. If the sensor is working, the multimeter will show a drastic change in readings. If you want to find a good multimeter, you can try this one on Amazon:
Innova 3340 Automotive Digital Multimeter (10 MegOhm/UL)
ir?t=askamastermec 20&l=am2&o=1&a=B000KIMHRQ

Step 4: Installing a new Sensor

Once the test is done and you are sure that the camshaft position sensor is not working, it is time to install a new one. Place the sensor in the same slot from which you removed the old sensor.

Step 5: New O-Rings

To ensure that the sensor is installed correctly, it is recommended that new O-rings are also installed. Also be sure to apply some engine oil to the rings before installing them. Install the new O-rings, place them on the cylinder and tighten the bolts.

Step 6: Attach the Wires to the Camshaft Sensor

Once the camshaft sensor is in place, connect the cables leading to the ignition system.

Step 8: Start the Engine

After installing the new camshaft position sensor, start the engine and take your car for a spin. Make sure that the car starts correctly this time and the check engine light disappears.

Camshaft Position sensor replacement cost

The average replacement cost for a camshaft sensor 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.

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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.

Diagnosing a failing Camshaft Sensor

The inspection of a defective camshaft sensor has a two-way diagnostic procedure. It is primarily confirmed by a physical diagnostic test. Secondly, you can observe the various problems it causes and the symptoms caused by a defective camshaft sensor. In order to effectively diagnose a defective camshaft sensor, you can follow a step-by-step process here that will help you with the diagnosis.

  • Observe the symptom of difficulty while starting your engine.
  • Check to see if a fault code is stored
  • Observe whether driving the vehicle feels different from normal
  • Check to see if the check engine light is illuminated.
  • Make sure by checking if the control unit has entered an emergency program.
  • By using an Ohmmeter, check the connection line from the control unit.
  • Remove the connectors from the control unit
  • Individually check the cables for continuity
  • Check the connection lines for a short circuit to the frame, the value should be above 30 MOhm.
  • Switch your multimeter to volts and check the supply voltage from the control unit to the sensor while the ignition is on. The reference values of your manufacturer can be found in the service manual. Normally the value should be around 5 volts.
  • After you have checked the supply voltage, check the signal voltage by connecting the cables from an oscilloscope, and switch on the engine. Check if there is a square wave signal on the oscilloscope, which should be the usual scenario.

9 thoughts on “ Camshaft Position Sensor Symptoms, Function & Location ”

  1. Very informative! Thank you so very much for sharing your knowledge with those who have no clue where to begin looking for information.

    1. Thank you for all your efforts trying to help us. Wishing you all the best.

  2. in order to check the camshaft sensor with passing a magnet what is the proper distance between the head of sensor and the magnet if the distance was more than the design distance with target wheel and still there is a drastic change in the multi meter reading is it still good sensor or failed?

  3. I appreciate your wealth of knowledge on the topic of Camshaft Position Sensor Symptoms!
    I recently replaced both the intake and exhaust sensors on my 2004 e46 SMG M3 and started perfectly, but apparently, since I did not tight battery terminals enough, it’s not received the correct voltage and the SMG pump is not engaging gears as it previously did! Your recommendations are welcome, if nay.

  4. very niceechanical information yesterday I was working on a KRUGER and all of the sudden it failed to start it couldn’t be on idling. I first thought of fuel and topped 12 litres and still it could behave like before checking on Google I found this important info which helped me to get the problem and solve it. Thanks very much

  5. yes thanks for those information regarding in camshaft position sensor…. please me more information and knowledge regarding complate automotive sensors details and there functions…

  6. I can get the bolt and wiring clip removed but the sensor is stuck tight and it won’t budge what do i do now

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