Throttle Position Sensor
From M-Tech Automotive
The Throttle Position Sensor (TPS) is a variable resistor that changes value based on throttle movement. The control module uses information from this sensor to adjust fuel delivery to compensate for throttle opening. Vehicles equipped with electronically shifted transmissions use information from the TPS to control transmission shifting as well.
Reference voltage is supplied to the TPS by the M-Tech ECU V-Ref wire, and changed by an internal variable resistor to output a signal relative to throttle position. The typical TPS will have a high resistance at closed throttle, that will steadily decrease as the throttle is opened. The signal produced by the TPS will be low voltage output at idle and a voltage output that reaches maximum reference voltage at full throttle, near 4.5 volts.
The sensor must be of this variable resistance type (usually having 3 wires) rather than the older 'switched' type.
By monitoring changes in the TPS signal voltage, the ECU is able to determine throttle angle and calculate fuel delivery accordingly.
For more information about mapping the ECU specifically using throttle position, refer to our 'Alpha-N Mapping Guide'.
