Throttle Position Sensor: Description and Operation

The position,sensor consists of a potentiometer connected to the throttle spindle.

The sensor is supplied with 5 V from ECM pin 42 and is grounded from ECM pin 67. The voltage from the sensor is connected to ECM pin 45 and is proportional to the accelerator setting.

The voltage is approx. 0.5 V during idling and approx. 4.5 V at wide open throttle. The ECM uses the voltage. from the sensor to identify idling, partly open throttle and wide open throttle. During idling the ECM uses a special ignition control matrix and adjusts the idling speed.

The closed loop is disconnected at wide open throttle.

Fuel injection is shut off at wide open throttle in conjunction with starter motor cranking.

A richer mixture is supplied during acceleration and a leaner mixture during deceleration.

Maximum boost pressure is also dependent on the position of the throttle. In the event of sensor failure or a break in the circuit, the engine control module will set wide open throttle as the default value