Throttle Position Sensor Description & Related Information
Nearly all post 96 vehicles use a throttle position sensor (TPS) to inform the engine control module of accelerator pedal and throttle plate position. TP 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. As the throttle opens, voltage returned to the computer from the Throttle 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. When testing the Throttle Position Sensor system, always make sure you have the 5 volt reference and return and then monitor the signal line for actual voltage output from the throttle position sensor. You can monitor this by back probing the circuit at the TPS. Voltage should steadily increase as throttle is opened. 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. You should also check while tapping and heating the sensor if you have a possible intermittent. See our article on Automotive Circuit Testing for more help with these tests, and always use appropriate caution.
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 check engine 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. A loosely mounted sensor will create erratic symptoms including rough idle, and hesitation so check this as well. Got more questions? Use the Get Help link and we'll assist! Thanks for stopping in and be sure to check out some of our very informative articles relating to check engine light repair!
If you find that you're in need of a replacement TP sensor, please visit one of our suggested parts suppliers. We research the leading companies for value and service and recommend only the best. You won't find better prices anywhere, and you can buy with peace of mind from reputable merchants! Thanks for stopping by, and have a great day!
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