Camshaft Position Sensor Symptoms: 7 Warning Signs of a Failing Sensor

The camshaft position sensor (CMP sensor) is integral to the modern vehicle. It helps to control the timing of the engine’s fuel injection and ignition systems. If the sensor fails, you can experience a variety of performance problems. Here are the symptoms and how to test and reset your CMP sensor.

7 Symptoms of a bad camshaft position sensor

An illuminated check engine light

One of the first symptoms is that the check engine light is on the dashboard. This may be due to several issues that this warning light indicates. Still, if the other symptoms are present, it is probably the camshaft position sensor.

Engine misfires

The incorrect transmission of error codes by the camshaft position sensor to the ECU using the wrong data can result in the engine’s ignition time being out of place. As a result, the engine might need to complete the proper combustion process. It might misfire, which you will feel as rough running or stuttering.

Poor fuel economy

A lousy sensor may disrupt the fuel injection sequence, making the fuel mixture very lean and the engine less efficient. You could notice you run out of fuel faster than usual, indicating a failing camshaft position sensor.

Rough idling

Incorrect sensor operation can force the engine to be bumpy when idling or driving, causing jerks or vibration. Similarly, you might need help in winding up your car. If the sensor transfers weak or no signals to the ECU, the engine may not start at all.

Difficulty Starting the Engine

While a faulty camshaft position sensor may not always prevent the engine from starting, it can make the process significantly more difficult. In some cases, the engine may crank but fail to start. This occurs because the sensor cannot accurately relay the camshaft’s position to the Engine Control Unit (ECU), which is crucial for proper fuel injection timing and spark plug firing. In severe cases where the sensor has completely failed, the engine may not start.

Poor Acceleration or Loss of Power

A malfunctioning camshaft position sensor can lead to noticeable performance issues, particularly during acceleration. Drivers may experience a lack of power when trying to increase speed, or the vehicle may feel sluggish and unresponsive. This symptom occurs because the ECU isn’t receiving accurate information about the engine’s valve timing, leading to suboptimal fuel injection and ignition timing.

Stalling or Intermittent Stalling

Another common symptom of a failing camshaft position sensor is engine stalling. This can happen while the vehicle is idling, at a stoplight, or even driving. The stalling occurs because the ECU needs consistent and accurate data about the camshaft’s position. Without this crucial information, the ECU may momentarily cut fuel or alter ignition timing, causing the engine to stall. Sometimes, the stalling may be intermittent, making diagnosis more challenging.

How to test a camshaft position sensor?

First of all, make sure your car is parked on a flat surface, and the engine is turned off. Locate the camshaft position sensor which is usually located near the camshaft or on the engine block. Once disconnected, the sensor resistance can be measured with a multimeter. With a multimeter, disconnect the sensor-wire and expose the probes to its one end. Set the multitester to the correct scale and measure the resistance across the terminals in the sensor. Use the manufacturer’s specifications table to find the correct resistance range for your specific vehicle. If the reading you’ve got is not within the scale mentioned, it suggests that the sensor you have is the one “in trouble” and then it needs to be replaced.

Furthermore, no proper voltage may be an output of the sensor, implying that the sensor may be failing or malfunctioning. The diagnosis can also be taken one step further. One of the options is diagnosing whether or not the sensor sends out a proper voltage reading. Then doing this, reconnect the sensor and use a digital storage oscilloscope to check the voltage across the pins. Yet, the service manual of your vehicle will tell you the ideal voltage specification. If the voltage varies or if it is missing, the sensor is the likely source of the problem.

How to reset a camshaft position sensor?

The first and most common technique for resetting a camshaft position sensor is the “clearing of the fault code” or the replacing of the sensor. You can reset the sensor by detaching the car battery. Firstly, turning the ignition off and removing the negative battery cable is the way to go. Giving the system a little while to “rest”, about 10-15 minutes, and later reconnecting the battery cable will do the trick.

On the other hand, using an OBD-II scanner to clear trouble codes is the next technique. You just need to follow these simple steps, and the trouble codes regarding the camshaft positioning sensor are then going to be cleared from the unit’s memory. Glory be that has a diagnostic connector. Unplugging the battery is the better option as the scanner clears data much faster and, as well, you avoid wasting battery power.

How long can I drive with a bad camshaft sensor

Driving a car with a poor camshaft sensor can be managed for a few short occasions, say, for up to a few hours, at best but it is never a good idea. The mentioned action can lead to malfunctions in the engine such as rough idling and misfires. The further you drive the car with this problem, the more likely engine cardiac arrest may occur or even the car will just stop.

Conclusion

Recognizing the signs of a bad camshaft position sensor, being able to check and reset it, and knowing the harms of driving with a faulty sensor will keep your automobile safe. If you feel that there is a problem, don’t be afraid to consult with a mechanic to avoid the engine from functioning smoothly and efficiently.