How many camshaft sensors are there?

Most vehicles have one or two camshaft sensors. The number of camshaft sensors depends on the engine design and configuration of the vehicle.

What is a Camshaft Sensor?

A camshaft sensor, also known as a camshaft position sensor, is an electronic device that monitors the position and rotational speed of the engine's camshaft. The camshaft sensor provides crucial information to the vehicle's engine control unit (ECU) about the timing of the engine's intake and exhaust valves. This data is used by the ECU to precisely control fuel injection and ignition timing, ensuring optimal engine performance and efficiency.

Single Camshaft Sensor Vehicles

Many vehicles, especially those with a single overhead camshaft (SOHC) engine design, have just one camshaft sensor. The sensor is typically located near the front of the engine, where it can monitor the rotation of the single camshaft.

Dual Camshaft Sensor Vehicles

Vehicles with a dual overhead camshaft (DOHC) engine design usually have two camshaft sensors, one for each camshaft. This allows the ECU to precisely track the timing of all the engine's intake and exhaust valves, which is essential for proper fuel and ignition control in a DOHC engine.

Reasons for Multiple Camshaft Sensors

• Improved Engine Control: Multiple camshaft sensors provide the ECU with more detailed information about the engine's valve timing, enabling more precise fuel and ignition adjustments for better performance and efficiency.


• Diagnostics: Having two camshaft sensors allows the ECU to detect discrepancies between the two camshafts, which can help identify mechanical issues with the engine.


• Redundancy: If one camshaft sensor fails, the ECU can still use the information from the remaining sensor to continue operating the engine, albeit with reduced performance and efficiency until the faulty sensor is replaced.

In summary, the number of camshaft sensors in a vehicle typically ranges from one to two, depending on the engine design. The sensors play a critical role in providing the ECU with the necessary information to optimize engine performance and efficiency.

How can I tell which camshaft position sensor is bad?

You can tell which camshaft sensor is bad by symptoms like the check engine light coming on, rough idle, poor acceleration, stalling, or difficulty starting. To confirm, use an OBD2 scanner to read trouble codes (P0340-P0349) and then inspect the sensor for physical damage or test its electrical signal with a multimeter.
 
This video explains the symptoms of a bad camshaft position sensor: 55sHonest Mechanic ColoradoYouTube · Nov 11, 2023
Common symptoms to look for

• Check Engine Light: This is often the first sign, indicating the car's computer has detected a problem with the sensor or its circuit. 
• Poor engine performance: You may notice sluggish acceleration, lack of power, or the engine sputtering. 
• Rough idle or stalling: The engine may run unevenly at idle or stall, especially at low speeds. 
• Difficulty starting: The engine may crank longer than usual before starting or fail to start altogether. 
• Poor fuel economy: An inefficiently running engine can lead to worse gas mileage. 
• Transmission problems: In some cases, a faulty sensor can cause issues with shifting gears. 

How to diagnose
This video demonstrates how to test the camshaft position sensor: 54sAuto Repair GuysYouTube · May 17, 2021

1. Use an OBD2 scanner: Connect a scanner to your car's diagnostic port to retrieve fault codes. Codes in the P0340-P0349 range specifically point to a problem with the camshaft position sensor or its circuit. 
2. Perform a visual inspection: Check the sensor and its wiring for any obvious damage, loose connections, corrosion, or signs of wetness. 
3. Test the sensor's signal: 
   • Disconnect the sensor: from its wiring harness. 
   • Use a multimeter set to the voltage setting. With the sensor unplugged, check that the voltage supply from the car's computer is correct (this step may vary depending on your vehicle, so consult a repair manual). 
   • Reconnect the sensor and have someone crank the engine. Watch the multimeter to see if the voltage signal fluctuates as the engine turns. A steady reading or no reading at all indicates the sensor is not sending a correct signal. 
   • To test resistance, you can also set the multimeter to the resistance setting and check the sensor's internal resistance to ensure it's within the manufacturer's specified range. 

Where are all the camshaft sensors located?

While the location of the camshaft position sensor(s) varies by application, it is commonly found on the cylinder head, at the timing cover or in the valve cover(s). Accessing the sensor may require removal of components such as the air filter housing, timing belt cover or other components.

How many camshaft position sensors are there?

The number of camshaft position sensors can vary, but vehicles typically have either one for a single overhead camshaft (SOHC) engine or two for a dual overhead camshaft (DOHC) engine with two camshafts per cylinder bank. More complex engines with variable valve timing (VVT) or V6/V8 configurations may have up to four sensors, with one for each intake and exhaust camshaft.
 
Factors that determine the number of sensors:

• Engine configuration: A simple single-cam engine will only need one sensor, while an engine with separate intake and exhaust cams will need a sensor for each, totaling two for one cylinder bank. 
• Number of cylinder banks: A V-shaped engine, like a V6 or V8, has two banks of cylinders. Each bank has its own camshafts, so a four-sensor setup would be common (two per bank). 
• Variable Valve Timing (VVT): Systems that adjust the camshaft timing often require an additional sensor to monitor the position of the intake or exhaust camshafts, particularly on newer vehicles with sequential injection. 
• Location: Sensors are typically located at the front or rear of the camshaft area, in the cylinder heads, or on the timing cover. 

How much should it cost to replace a camshaft sensor?

The total cost to replace a camshaft sensor typically ranges from $185 to $650, but can vary based on vehicle type and labor rates. The cost is a combination of parts and labor, with the part usually costing between $20 and $150 and labor costing between $80 and $500+ depending on accessibility and shop rates. 
Cost breakdown

• Parts: The camshaft sensor itself is relatively inexpensive, usually costing between $20 and $150. 
• Labor: Labor costs can vary significantly. Shops typically charge an hourly rate and the time to replace the sensor can be under an hour for simple jobs, or up to two hours or more for more difficult-to-reach sensors. 
• Diagnosis: Some shops may charge a separate diagnostic fee, which can range from $120 to $200, but this fee is often applied to the total repair cost if you proceed with the service. 
• Vehicle Type: The final cost will depend on your car's make, model, and year. Luxury or more expensive vehicles may have higher parts costs and labor rates, increasing the overall price. 

How to save on replacement costs

• Get multiple quotes: Contact both independent mechanics and dealerships to compare prices for both parts and labor. 
• Do it yourself: If you are comfortable with car maintenance, replacing the sensor can save you the cost of labor, as it can be a straightforward job. 
• Use the right parts: Some recommend using Original Equipment Manufacturer (OEM) or Tier-1 (Bosch, Denso, Delphi) parts to avoid future issues, especially for critical sensors.