Tips for Replacing Camshaft & Crankshaft Position Sensors

How Camshaft & Crankshaft Position Sensors Work

Vital to engine performance, the camshaft position sensor and crankshaft position sensors are designed to ensure that the ignition and fuel injection information properly powers the vehicle. While both provide information to the Electronic Control Unit (ECU), each track different engine components.

The camshaft position sensor(s) records the position of each camshaft as it rotates. The ECU uses the information from this sensor to optimize spark timing, fuel injection, and provide the ECU with the camshaft’s position for variable valve timing (VVT) ensuring efficient engine performance. The crankshaft position sensor detects the precise position of the crankshaft as it rotates. The data that is sent to the ECU is used to calculate ignition timing, fuel injection timing and engine RPM.

Working together, the information from these sensors tells the ECU when conditions are right to initiate provide spark and fuel for the combustion process.

Locating the Camshaft Sensor(s)

While the location of can vary by application, the camshaft position sensor(s) are often found on the cylinder head, at the timing cover or in the valve cover(s). To access the sensor, it may be necessary to remove the air filter housing, timing belt cover or other component. A repair manual for your vehicle can help you find the location of the sensor.

Locating the Crankshaft Position Sensor

The crankshaft position sensor is usually found on the lower end of the engine. They may take their readings off the flywheel teeth or a relucator wheel on the crankshaft. A repair manual for your vehicle can help you find the location of the sensor. 

Removing the Old Camshaft or Crankshaft Position Sensor

These general steps will help you remove the old camshaft position sensor or crankshaft; please note that specific steps may differ for your vehicle.

Getting Ready

Allow the engine to completely cool down before removing a sensor and safely jack up the vehicle if you need to go under the vehicle to reach a sensor.

Gather the Right Tools 

Having the necessary tools on hand will make the job a bit easier. You’ll need a socket or wrench to remove bolts, a torque wrench to tighten the bolts to the proper specifications and a screwdriver to remove covers and disconnect wires.

Disconnect the Power

Disconnect the negative battery terminal to prevent a short circuit. This crucial step should be taken anytime you work with sensors or electrical components. Some crank position sensors may require the removal of exhaust components or the starter.

Remove the Connector 

Inspect the connector for damage, corrosion or dirt which can affect the sensor’s signal to the ECU. Dirt in the connector tab area may make it difficult to release the locking tab plus you don’t want dirt getting into the engine. Some sensor connectors may have a locking tab that needs to be slid back first to allow the release of the primary locking tab. The locking tab is usually a different color than the main connector.

Remove the Sensor

Remove the screws with a socket and ratchet or wrench and gently twist the sensor to take it out. Clean the bore where the sensor fits into. 

Installing the New Camshaft or Crankshaft Position Sensor

Follow these tips to successfully install the new camshaft position sensor or crankshaft position sensor.

Compare the Sensor

Before installing the new sensor, compare it to the old one to ensure they match exactly.  

Check the O-Ring

The O-ring keeps dirt from getting in and prevents oil from leaking out of the sensor hole. When removing the old sensor, make sure the O-ring doesn’t fall into the engine block. Use a new O-ring when installing the sensor and lubricate it with small amount of clean engine oil.

Install New Sensor

Put new sensor into place and install mounting bolts; use torque wrench to tighten bolts to manufacturer’s specifications.

Reconnect Electrical Signal 

Restore the signal to the ECU by plugging in the electrical connector.

Replace Components 

Replace any parts that you had to remove to access the sensor.

Reconnect Battery

Hook the negative battery terminal back up.

Clear Codes

After installing the new sensor, start the engine and make sure the check engine light isn’t illuminated. You may need to clear the code with an OBDII scanner to turn the light off.

Resetting the Sensor

When installing a new crank position sensor, it is sometimes necessary to calibrate the sensor with a scan tool. Failing to reset the sensor can cause it to produce incorrect data which can result in increased emissions, poor engine performance, hard starts, rough idling and lower gas mileage.

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The content in this article is for informational purposes only. You should consult with a certified technician or mechanic if you have questions relating to any of the topics covered herein. Tenneco will not be liable for any loss or damage caused by your reliance on any content.