Throttle Position Sensor: Description and Operation

Throttle Posittion Sensor:

THROTTLE POSITION SENSOR

The Throttle Position Sensor (TPS) is a potentiometer mounted at the throttle butterfly converts throttle position into an electrical signal used by the ECM (along with data from the Mass Air Flow Sensor) to determine the volume of air entering the intake manifold.

GEMS throttle circuitry is adaptable within a range of 80 to 500 mV. Within this range, the PCM will adapt to the initial setting and use it as a reference. There is no need to adjust the TPS following installation on these models. If the TPS should fail, the ECM will use a default value of 576 mV and the MIL will be illuminated.

A diagnostic trouble code is set when sensor output is less than 78 mV for longer than 160 milliseconds.

Acceleration Enhancement

The ECM increases the amount of fuel normally provided for a given throttle position during periods of peak acceleration. This allows the system to anticipate fuel needs.

Deceleration Fuel Shut-off

During throttle closed deceleration, the ECM does not activate fuel injectors (zero pulse-width) to prevent unneeded fuel from entering the cylinders. This strategy protects against catalytic converter overheating and reduces fuel consumption.