The TPS sensor is connected to the throttle shaft at the TBI unit.
The Throttle Position Sensor (TPS) is a Linear Potentiometer that monitors the throttle position. The TPS operates within a 5 volt DC reference range, and provides a linear input signal to the Powertrain Control Module (PCM). The PCM uses data from the TPS to calculate air-fuel mixture, ignition timing, fuel injector pulse width, and transmission/transaxle gear position.
Removal & Installation
Before servicing the vehicle, refer to the Precautions Section.
NOTEDisconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.
NOTEIf working near and/or around the SRS system and components, be sure to properly disable the SRS system. See disarming/arming the SRS system.
- Disconnect the negative battery cable.
- Disconnect the TPS electrical connector.
- Remove the 2 mounting screws.
Remove the TPS and, if equipped, TPS seal from the throttle body.
- Place the TPS in position. Align the TPS lever with the TPS drive lever on the throttle body.
- Install the 2 TPS mounting screws.
- Connect the electrical connector.
- Connect the negative battery cable.
- Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.
Connection & Wiring Diagnosis
Refer to the Electrical Wiring Diagram for component and connector locations, connector views, and circuit-specific information.
Many intermittent open or short circuits may be caused by wiring harness and connector movement due to vibration, engine torque, bumps and rough pavement, etc.
Test the wiring harness and connectors by performing the following tests:
Move the related connectors and wiring while monitoring the appropriate scan tool data.
Test the connector terminal pins and/or wiring by performing the following tests:
Inspect for incorrect mating of the connector halves, or terminals not fully seated in the connector body.
A properly operating TPS should display a linear -sweep- of the entire throttle range, and should not exhibit any voltage drop or signal break. If the feedback signal is not within the specified range, additional diagnosis is required in order to determine the proper function of the TPS, or if a fault exists in any related sub-systems.
The TPS provides a linear input signal to the Powertrain Control Module (PCM), which is used to monitor the throttle position. The TPS monitors the entire range of throttle opening from 0.5 volts DC (0%) 4.5 volts DC (100%). In modern drive-by-wire throttle control systems, the TPS provides data to the PCM in order to calculate the desired throttle position, in addition to air-fuel mixture, ignition timing, fuel injector pulse width, and transmission/transaxle gear position.
The TPS utilizes positive coefficient logic: as the accelerator position is increased, the voltage is increased.