Nearly all post 96 vehicles use a throttle position sensor.TPS sensors are normally mounted on the throttle body with the throttle plate shaft running into the sensor. As the gas pedal is pushed, the throttle plate opens, rotating the sensors internal variable resistor. Position Sensor varies (normally increasing), signaling the rate of throttle opening as well as throttle position. The computer uses this information to adjust fuel trim, which is the amount of time the injectors are open , delivering more fuel.
Most throttle position sensors have at least 3 wires. These are for a 5 volt reference, a return line and the actual TPS voltage line. With your own digital volt meter you can actually see the 5 volt reference change as you open and close the throttle shaft. This should be checked with the key on and engine off. Use and appropriate wiring diagram and always verify correct base voltage before sweeping the gas pedal. Any erratic dropping or spiking voltage indicates a concern. Remember to check and pierce the return wire and watch the voltage going back to the computer. You should also check while tapping and heating the sensor if you have a possible intermittent.
Possible symptoms of a faulty TP sensor include hesitation or stumble on acceleration or tip in, a dead spot in the throttle, rough idle or service engine soon light with related codes. Some older style throttle position sensor are adjustable, but most newer style sensors are fixed position. Base TPS voltage readings are critical for proper fuel trim operation so always use your scan tool or multimeter to check for a good setting. Like I said before, these can be purchased through Amazon on the Caracal Link to the right! A loosely mounted sensor will create erratic symptoms including rough idle, and hesitation so check this as well. If you are planning on doing some of this minor repair engine control system testing plan on purchasing your own Code reader, Digital multimeter and possibly your own scan tools from Amazon!
Happy driving!
