The TPS (throttle position sensor) in your Saturn S-Series car is a variable resistor sensor, mounted on the throttle body, that supplies a varying voltage signal to the on-board computer. By converting some of a 5-volt reference signal into heat, the sensor changes the return voltage to the computer that indicates the percentage of throttle opening. The TPS in the Saturn S-Series is not adjustable and can only be installed on the throttle body in the correct position. The average home mechanic needs only basic hand tools to remove and replace this sensor.
Remove the negative battery cable from the battery terminal using an 8 mm wrench. In the Saturn S-Series, the battery is located between the air filter housing and the master cylinder on the driver-side of the engine compartment.
Remove the air filter housing cover and duct that attaches the filter housing to the throttle body. Use your thumb to unsnap the four retaining clips on the cover. Insert a screwdriver into the plastic duct clamp and release the clamp. Unplug the vent tube from the duct and lay the duct and cover aside.
Locate the TPS on the back of the throttle body between the intake manifold and the firewall. The TPS is on the opposite side of the throttle body from the throttle cables and is actuated when the cables move the throttle shaft. Remove the electrical connector from the TPS by lifting the locking tab up with a screwdriver and pulling the connector out of the TPS.
Remove the two T-20 size torx screws that attach the sensor to the throttle body using a T-20 socket and ratchet. Begin with the lower screw as it is the most difficult to access. Slide the old TPS off the throttle shaft and note that the throttle shaft is flat and engages the rotating disc in the center of the TPS.
Align the throttle shaft with the center of the TPS and push the TPS onto the shaft. Rotate the TPS until the locating pin on the body of the sensor aligns with the locating hole in the throttle body, and press the TPS into place on the throttle body.
Reinstall the two torx screws and tighten them snugly. Reinstall the electrical connector and press it into the TPS until the locking tab snaps into place. Reinstall the air duct and air filter housing cover. Reinstall the negative battery cable.
