Top 6 Symptoms of Bad Camshaft Sensor
February 19, 2023

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A camshaft position sensor is an electrical component found in most vehicles. The camshaft position sensor and the crankshaft position sensor are similar.
However, the two have very different functions. They are both used to performing varying tasks in a vehicle, and it develops symptoms when something goes wrong.
The position sensor can wear down or fail due to normal wear and tear or accidents. If the sensor fails, it can shut down the engine, which makes replacement necessary. There are a couple of warning signs that you should watch out for before it fails.
Let’s talk about the symptoms of a bad camshaft sensor and how much it would cost to replace it if it's defective.
Table of Contents
What Is a Camshaft Sensor?
The core function of the camshaft sensor is to work in conjunction with the vehicle's crankshaft sensor.
It's designed to determine the position of the drive camshaft accurately. This allows the engine to determine the first cylinder's time in the dead-center position.
The engine system uses the information collected by the camshaft for various purposes.
For instance, it can start the sequential injection process and provide the necessary information to the pump nozzle injection system.
The Hall principle is a core working concept of the camshaft sensor. When a ring gear is rotated, its rotation causes a change in the voltage level of the Hall IC in the sensor head. This leads to a change in the control unit's voltage transmission.
The information collected by the camshaft is then electronically evaluated and stored by the computer system.
A bad camshaft can affect the functionality of the position sensor, which can cause various issues for the vehicle's overall performance.
Symptoms of Bad Camshaft Sensor
The following are symptoms of a bad camshaft sensor:
1. Check Engine Light Comes On
The failure of the camshaft position sensor usually triggers the light on the check engine light.
In most cases, the only symptom of a bad camshaft sensor is this light on the dashboard.
If the light on the check engine light continues to blink, you must take your vehicle to a car specialist to have it checked.
Doing so can help identify potential trouble codes. Unfortunately, many ignore this light even though it could indicate serious issues, such as engine damage.
2. Poor Engine Performance
If the vehicle starts to idle roughly, experience a drop in engine power, accelerate slowly, or decrease gas mileage, the position sensor might fail.
These are the symptoms that can trigger the need for the replacement of the position sensor.
It should be done right away to prevent the engine from starting or dying while you're driving. It's also important to note that this issue can affect other problems.
3. The Vehicle Will Not Start
If the other problems are not addressed, the vehicle will not start. The weakening of the position sensor can also affect the signal it sends to the engine's ECM.
This issue can occur while the vehicle is parked or while you're driving. It can lead to a dangerous situation.
If your vehicle is not moving like it used to, the sensor might need to be replaced. This issue should be addressed as; eventually, the engine will stop working.
4. Engine Misfire & Vibration
A poor camshaft sensor can also cause misfires, which can cause engine vibrations while the vehicle is accelerating.
If you notice that your vehicle's performance has decreased, you must have it checked.
5. Bad Fuel Consumption
If the vehicle's power is decreased due to the faulty position sensor, it can also cause higher fuel consumption.
This issue is usually rare, but it's essential to check the codes related to the position sensor.
6. Problems with Shifting Gears
If the car has automatic transmission, it won't shift gears properly if it has a faulty camshaft position sensor. This issue could be caused by the trouble code found in the position sensor.
Camshaft Sensor Troubleshooting
If the computer has already started to trigger the engine light, then you can try to retrieve the DTC by using a scan tool or a code reader.
If you can't afford a code reader, you can still drive safely by visiting a parts store that provides free DTCs.
After you have confirmed that the position sensor has a problem, it's vital to perform some simple tests to check its condition.
A code indicating a potential sensor failure doesn't mean the sensor is defective. A component failure or a wire, or a connector could cause it.
Although a scope is required to confirm the operation of the camshaft sensor, it's also essential to check its condition. This can be done with the use of a digital multimeter.
Check the condition of the wires and electrical connectors of the sensor.
After you have disconnected the connectors, inspect for contamination or rust, which might interfere with the sensor's electrical contact.
Also, ensure that the wires are not touching the wires of the ignition coils or spark plug.
Depending on the type of sensor, the digital multimeter may be able to test either direct current or alternate current voltages.
To ensure that the sensor's electrical values are correct, it's essential to look through the vehicle's repair manual.
Some types of sensors allow you to back-probe the wires through their electrical connectors.
If this isn't possible, try unplugging the sensor and attaching a copper wire to the terminals. Then, plug the two strands out through the housing of the connector.
One of the most common ways to test the wires is by piercing them using a pin.
Doing so should be done carefully, and electrical tape should be used to cover the pin holes. If you do this, it will prevent corrosion build-up.
Testing a Two-Wire Sensor
If you have a magnetic-type sensor with two wires, set the multimeter to "AC volts." Ask an assistant to turn on the ignition key without starting the engine.
Check if there's power flowing through the circuit. One of your probes should be touching one of the wires, while the other should be touching the ground. If there's no current, the sensor might malfunction.
Ask the same assistant to start the engine. To test the sensor, touch one of your meter probes to one of the wires and the other to the other wire.
Check the display to ensure the readings are within your manual's specifications.
You most likely have a bad camshaft sensor if there are no readings.
Testing a Three-Wire Sensor
Using your vehicle's repair manual, identify the wires and power coming from the sensor. Test the device's circuit by setting the multimeter to "DC volts."
Have someone help you turn the ignition key without starting the engine.
To test the sensor, touch one of your meter's black probes to the ground and the other to the power wire. Check the readings to ensure they're within your manual's specifications.
Start the Engine
The red probe from your meter should be used to inspect the signal wire, while the black search should be used to test the ground wire.
Check the readings to make sure that they're within the specifications of your vehicle's repair manual.
After you've removed the sensor, inspect it for signs of contamination or physical damage.
Where Is Camshaft Sensor Located?
The exact location of the sensor can vary depending on the make and model of the vehicle.
Most cars have a sensor located near the cylinder head. However, some models have special compartments for the sensors. You can also look for it near the rear end or the top section of the timing belt.
Some Nissan Quest and Mercury Villager models feature the CMP sensor inside their distributor housing. Some Dodge Ram models, B1500 and B2500, have similar features.
Some Nissan Quest, Mercury Villager, and Dodge Ram models utilize the same distributor housing.
Some newer B1500, B2500, and B3500 series cars and some gasoline-powered vehicles may have one or more cam sensors.
Some models of the Nissan Quest, Mercury Villager, and Dodge Ram utilize the same distributor housing.
Some newer B1500, B2500, and B3500 series cars have similar features. Some car models may have one or more cam sensors.
If you have a problem with the sensor, you can check your vehicle's service manual for the make and model of the car you're interested in.
You can also find a copy in the public library's reference section. An aftermarket repair manual can help you perform minor repairs and maintain your vehicle.
Camshaft Sensor Replacement Cost
If the camshaft position sensor is not working correctly, you should replace it. Doing so can be as simple as removing the electrical connection and the mounting bolt. You might have to remove other components to access the sensor on other models.
If you have a problem with the sensor, you can check your vehicle's service manual for the make and model of the car you're interested in.
It should explain how to replace the sensor. Depending on the model, you should spend around $30 to $100 for the sensor.
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