What is a Camshaft Sensor on Vehicles

by Contributing Writer; Updated June 12, 2017

The camshaft position sensor on a Vehicles is a digital sensor that creates an on and off pulse that tells the engine computer where the valve train is positioned relative to the crankshaft of the engine. The computer decides when the fuel injectors should fire based on this information.

Under The Hood:

 What is a Camshaft Sensor on a Grand Prix?

How it Works

A magnet is mounted on the outer part of a ring attached to the engine camshaft. The camshaft position sensor is near that ring. As the magnet approaches the sensor in its rotation, it produces electric current, or a pulse. The speed and timing of these pulses determines valve train position and speed.

Location

The camshaft position sensor mounts on the front of the engine, just above the crankshaft pulley. It is also to the left lower side of the serpentine belt idler pulley. The sensor typically has two wires leading from it.

Removal

The camshaft position sensor is held in by one bolt. Remove that bolt, and disconnect the electrical plug to remove the sensor from the engine.

 Where Is the Camshaft Sensor on an '03 CTS?

Removal

Lift the vehicle hood and support it with the hood prop rod.

Disconnect the electrical connector from the camshaft position sensor pigtail by gently prying up on the tab with your thumb and pulling the connectors apart. Remove the knock sensor pigtail retainer.

Remove the securing male Torx bolt with the female Torx socket and ratchet from the camshaft sensor.

Gently pull the camshaft sensor out of its mounting hole in the bearing cap.

Installation

Spray brake cleaner on the shop rag and clean the mating surface on the camshaft bearing cap.

Set the camshaft position center into the camshaft bearing cap and secure it with the male Torx bolt. Tighten the bolt to 71 inch-pounds with the torque wrench.

Attach the knock sensor pigtail retainer by clipping it into place on the camshaft position sensor.

Plug the wiring harness into the camshaft position sensor pigtail. Shut the vehicle hood.

Items you will need

  • Socket

  • Female Torx bit set

  • Brake cleaner

  • Shop rag

  • Small torque wrench

 Where Is a Camshaft Sensor in an Engine?

Location

Because a camshaft sensor may be magnetic, it will often be found positioned directly on the timing cover located over the gear of the camshaft. It can also be located either inside a special type of housing that takes the place of the distributor, or inside the distributor itself.

Functions

Some vehicle engines have distributorless ignition systems. When this is the case, a camshaft sensor's role is to notify the motor's control module of the position of the camshaft as well as the crankshaft. The information taken from the camshaft sensor is then used to assist with proper ignition timing.

Diagnosis

Many vehicles model year 1995 or newer can be checked for camshaft sensor problems using a scan tool. Once it is plugged in, the scan tool reveals certain fault codes if there is a problem. For example, fault code P0342 indicates low input in the camshaft sensor's circuit.

About the Author

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