Engine Speed Sensor: Description and Operation

PURPOSE
It generates an RPM signal to the Powertrain Control Module (PCM).

OPERATION
The engine speed sensor input is used along with the vehicle speed sensor and throttle position sensor (TPS) inputs to determine when to shift the automatic transmission into and out of overdrive. The speed sensor signal is also used as an input for the Automatic Shutdown relay (ASD) (for control of generator field), vehicle speed control, torque convertor electrical engagement and instrument panel mounted tachometer.

CIRCUIT OPERATION
Circuit K6 supplies 5 Volts from the Powertrain Control Module (PCM) to the engine speed sensor. The K6 circuit connects to cavity A17 of the PCM connector.

Circuit K24 from the engine speed sensor provides an input signal to the PCM. The K24 circuit connects to cavity A8 of the PCM connector.

The PCM provides a ground for the engine speed sensor signal (circuit K24) through circuit K4. Circuit K4 connects to cavity A4 of the PCM connector.