Camshaft Position Sensor: Description and Operation

The camshaft position sensor is mounted adjacent to the front exhaust camshaft sprocket. It is of Hall-effect type and supplied with power from the main relay and connected to ground at grounding point G37.

The exhaust camshaft sprocket has a hub with a ridge which passes the Hall-effect sensor once per camshaft revolution. The sensor output is connected to pin 38 of the control module.

The control module applies 12 V to the lead. When the large hole in the crankshaft position sensor's slotted One passes the sensor and piston No. 1 is on its compression stroke, the camshaft sprocket's ridge will pass the camshaft position sensor and the lead connected to pin 38 of the control module will be grounded by the Hall-effect sensor element.

The sensor is also known as a phase sensor because it indicates which of the pistons having the same crankshaft order is on its compression stroke. A phase sensor is essential for sequential fuel injection and knock control.

Should the sensor fail to work or in the event of a break in the circuit (no continuity), the ignition will be retarded so that the engine can run without knocking throughout the entire throttle opening/engine rpm range.