T.P sensor.

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This sensor is one of many main input sensors on vehicles that are on our roads to date using computer equipped engines (ECU). This sensor is a potentiometer (variable resistance sensor) which is a three wire sensor. One for 5volt reference wire, one for ground and the other your signal wire that relays information to the ECU. Depending on whether the contact is closer to the supply or the ground end of the resistor that's in the sensor, return voltage is high or low.  The ignition and fuel timing is determined by the TPS. The ECU uses information from the sensor to determine position of the throttle valve.   At idle, throttle valve would be closed  which means high resistance telling ECU  as called vacuum. As it  throttle valve opens resistance lowers, ECU determines from the potentiometer how far it has opened and tells injectors to deliver fuel in proportion to the air depending on valve position. Other functions of a TPS is torque converter clutch operations in a automatic transmission and clear flood mode operations. This is when throttle is WOT at cranking, ECU will either minimise or fully eliminate any pulsing for injectors to help clean a flooded engine. If its at WOT and engine is not flooded, the engine may not start. This sensor also backs up another sensor in a vehicle that's computer equipped. If MAP/MAF sensor were faulty, ECU would be able to calculate fuel needs and spark timing through readings from RPM and position of throttle valve. Typical TPS voltage at idle is about 10% of WOT meaning when gas pedal is touching the floor, that voltage reading you get, 10% of the reading is what it will be about at idle.


TESTING WITH DMM (DIGITAL MULTIMETER).

• Turn KOEOF
• Measure the voltage between signal wire and ground wire.Voltage should be around 0.5volt.
• Still KOEOF, slowly open throttle, in doing so voltage on DMM should also increase as throttle opens. If its reading OL (over load, open circuit) sensor is faulty and needs replacing.
• Now slowly return throttle back and voltage should also decrease as throttle closing.