Throttle Position Sensor Voltage Check

[slowEJ6]

1. Follow the wiring harness from the TPS to the back of the intake manifold and remove it from the firewall. This will give you more room to probe the electrical terminals. Check the electrical connector @ the sensor for a snug fit. Check the terminals in the connector and the wires leading to it for looseness and breaks. Repair is necessary.
2. Using a voltmeter, check the reference voltage from the ECM/PCM. Connect the positive probe to the yellow/blue wire and the negative probe to the ground. It should read app. 5 volts.(you will see 3 diff segments on the TPS - from right to left - 1st segment is Power, 2nd segment is Signal, and 3rd segment is Ground).
3. Next, check the TPS signal voltage. With the engine OFF, throttle fully closed and TPS electrical connector connected, connect the probes of the voltmeter to the red/black wire (positive probe) and ground (negative probe). Note: use a straight pin to backprobe the connector terminal. Gradually open the throttle valve and observe the TPS voltage. With the throttle valve fully closed, the voltage should read about 0.5v. Slowly move the throttle valve and see if the voltage changes as the sensor travels from idle to full throttle. The voltage should increase smoothly to about 4.5v. If the reading are incorrect, replace the TPS sensor.
4. A problem in any of the TPS circuits will set a code. Once a trouble code is set, the ECM/PCM will use an artificial default value for TPS and some vehicle performance will return.