Camshaft Position Sensor: Description and Operation

Camshaft Sensor:

PURPOSE
The camshaft position supplies an input signal to the ECU regarding which pair of pistons (1-6, 2-5, 3-4) is approaching TDC. This information, combined with crankshaft speed and position signals, allows the ECU to adjust ignition timing and injection duration for the proper cylinder(s).

LOCATION
Mounted at the rear of the cylinder head on the exhaust side camshaft.

COMPONENTS
The camshaft position sensor consists of a Hall effect switch, trigger rotor, and cover.

1-2-4 Ignition:

3-5-6 Ignition:

OPERATION
As the rotor rotates with the camshaft, it alternately shields and exposes the Hall switch, generating high (5 V) and low (0 V) signals.

The trigger rotor vane and opening are the same width so only one signal is produced per crankshaft revolution. During 5 V signals, the ECU controls outputs for cylinders 3, 5, and 6. During 0 V signals, the ECU controls outputs for cylinders 1, 2, and 4.