Mazda Throttle Position Sensor
The Mazda Throttle position sensor (TPS) is basically a sensor that monitors
the position of the throttle valve. It is located at the throttle shaft on the
throttle body. It converts the throttle valve angle into an electrical signal.
The engine control unit (ECU) uses the throttle valve position information in
order to monitor: engine mode (idle, part throttle, wide open throttle), switch
off AC and emission controls at wide open throttle, air/fuel ratio correction,
power increase correction, and fuel cut control. This sensor is usually a potentiometer
that provides a variable resistance relatively depending on the position of the
valve.
The Mazda throttle position sensor is essentially needed by the ECU as an input
to its control system. All critical engine operations are determined using this
sensor such as the ignition and fuel injection timing. All are altered depending
on the position of the throttle as well as the rate of change of that position.
For instance, in fuel injected engines, to prevent stalling, extra fuel can be
injected when the throttle is opened quickly. Today, more advanced designs of
the sensor are used such as the extra closed throttle position sensor (CTPS) that
may be used to indicate that the throttle is closed completely.
Typical throttle position sensor employs three wires, wherein 5 volts are supplied
to the TPS from the VC terminal of the ECU. A ground wire is connected from the
TPS to the E2 terminal of the ECM which completes the entire circuit. At idle,
the voltage stays at approximately 0.6-0.9 volts on the signal wire, and from
this voltage, the ECU detects that the throttle plate is closed. During wide open
throttle, the signal voltage may range at 3.5-4.7 volts. Some ECU’s also manages
the throttle position, and when it is done, the position sensor is used in a feedback
loop, enabling that control.
A resistor and wiper are mounted inside the Mazda throttle position sensors.
The arm makes constant contact with the resistor and at the point of contact a
voltage is created which serves as the signal voltage, indicating throttle valve
position. At idle, the resistance of the VC and VTA terminal is high and thus,
the created voltage is low approximately at 0.6-0.9 volts. As the contact arm
moves closer into the VC terminal, the resistance decreases and the voltage signal
increases. Some throttle position sensor have closed throttle position switch.
This switch is closed as the throttle valve is closed and opens when the throttle
valve opens.
The Mazda throttle position sensor should be maintained constantly to ensure
its top working condition. If damage is incurred due to its normal wear after
several years of use, a replacement must be done. If you have any doubts on its
condition, have it checked by a qualified service technician for proper diagnosis
and for possible replacement installation. Complete lines of Mazda throttle position
sensors and the rest of the Mazda auto parts are now available.
