Monte Carlo V6-3.4L VIN E (2000)
Throttle Position Sensor: Description and Operation
The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. By monitoring the voltage on the signal line, the
PCM calculates throttle position. As the throttle valve angle is changed (accelerator pedal moved), the TP sensor signal also changes. At a closed throttle
position, the output of the TP sensor is low. As the throttle valve opens, the output increases so that at Wide Open Throttle (WOT), the output voltage
should be above 4.0 volts.
The PCM calculates fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor may cause intermittent bursts of fuel from
an injector and unstable idle because the PCM thinks the throttle is moving. A hard failure in the TP sensor 5.0 volt reference or signal circuits should
set either a DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage. A hard
failure with the TP Sensor ground circuit may set DTCs DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage, DTC P0112
Intake Air Temperature (IAT) Sensor Circuit Low Voltage, DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage, or DTC P0117 Engine
Coolant Temperature (ECT) Sensor Circuit Low Voltage. Once a DTC is set, the PCM will use an artificial default value based on engine RPM, engine
load and mass air flow for throttle position and some vehicle performance will return. A high idle may result when either DTC P0122 Throttle Position
(TP) Sensor Circuit Low Voltage, or DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage is set.
The PCM can detect intermittent TP sensor faults. DTC P1121 Throttle Position (TP) Sensor Circuit Intermittent High Voltage, or DTC P 1122 Throttle
Position (TP) Sensor Circuit Intermittent Low Voltage will set it an intermittent high or low circuit failure is being detected.
