General description
Throttle position sensor (TPS) located on the throttle shaft shank on the throttle body. By continuously monitoring the output voltage from the TPS, the ECM/PCM determines the correct fuel delivery based on the throttle angle (according to the pressure on the pedal "gas"). A damaged or loose sensor can cause erratic fuel delivery from the injectors and erratic idling, as the ECM/PCM responds to such faults as if they were throttle movements.
Examination
25. To check the sensor, set the ignition key to position "ON" (without starting the engine) and connect tester leads to "mass" and signal wires on the back side of the sensor electrical connector (see illustrations).
4.25a. On a 3.1 liter engine, the voltage should be between 0.6-4.4 V. Connect the positive tester lead to the contact "IN", and negative - to the contact "A" (closed on "mass") | 4.25b. On a 3.8 liter engine, the voltage should be between 0.4-4.2 V. Connect the positive tester lead to the contact "IN", and negative - to the contact "WITH" (closed on "mass") |
26. When the accelerator pedal is not pressed (which corresponds to the operation of the engine at idle) the tester should show voltage in the range of 0.25-0.98 V. Ask an assistant to press the accelerator pedal, simulating a fully open damper - the voltage from the sensor should increase to 4.0-4.8 V. If the voltages you measured do not correspond to the values \u200b\u200bgiven above, replace the sensor.
27. Next, measure the resistance of the sensor. To do this, disconnect the electrical connector from the sensor and connect the tester probes to its contacts (see illustrations). Slowly opening the throttle, observe the readings of the tester (with the transition from idle to full open operation, the resistance value of the sensor should change noticeably).
4.27a. On a 3.1 liter engine, the resistance should be in the range of 1100-5600 ohms. Connect the positive tester lead to the contact "IN", and negative - to the contact "A" (closed on "mass") | 4.27b. On a 3.8 liter engine, the resistance should be in the range of 1400-4700 ohms. Connect the positive tester lead to the contact "IN", and negative - to the contact "WITH" (closed on "mass") (the sensor in the photo has a resistance that is outside the required limits) |
28. If any of the sensor circuits fails, a code 21 or 22 is sent to the control unit. When a DTC is received, the ECM / PCM will use a certain conditionally set value as a signal from the sensor and the engine will recover to some extent.
Replacement
29. If it is necessary to replace the throttle position sensor, refer to the full description of this procedure contained in section 12 chapter 4 (for engines 3.1 l) or in section 13 (for 3.8 l engines).