The throttle position sensor has both an idle contact switch and a basic 3 wire potentiometer that measures throttle angle opening. The idle switch and the throttle potentiometer share a ground wire.
To test the sensor first you have to verify that the wiring is intact by
1. Disconect the sensor and with a volt meter check the 4 wires. I have attached a wire diagram and picture of the pin layout to make it easy for you.
Pin 1 ( Yellow wire) is the PCM reference voltage. Specification is 5V
Pin 2 ( Red and Green wire) is the signal wire for the TPS. Specification is 5V
Pin 3 (Blue and white wire) is the idle switch. Specification 5V. Please note that this circuit is not actually used by this year Sedona so some vehicles are missing the wire.
Pin 4 (Black and yellow wire) is the ground. Specification: continuity to ground ( less than 1 ohm)
If the voltages are correct next you want to check the sensor.
1. Connect the throttle sensor connector.
2. Key on engine off
3.With a voltmeter measure terminal 2 of the sensor with the throttle closed, Specification is .2 to.4 volts.
4. With ta voltmeter monitor terminal 2 with the throttle fully open.The specification on terminal 2 is 4 to 4.4 V.
5. Slowly open and close the throttle while monitoring terminal 2 and make sure you have a smoot increase and decrease in voltage as the throttle is moved from close to open throttle and returned to idle.