Roadmaster Estate Wagon V8-350 5.7L VIN P SFI (1996)
Throttle Position Sensor: Description and Operation
DESCRIPTION
The Throttle Position (TP) sensor is a potentiometer. The TP sensor is 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.
OPERATION
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. This may cause an unstable idle because the PCM detects the throttle is moving.
When the PCM detects a malfunction with the TP sensor circuits, the following DTCs will set:
^
DTC P0121 circuit performance malfunction.
^
DTC P0122 circuit low.
^
DTC P0123 circuit high.
^
DTC P1121 intermittent circuit high.
^
DTC P1122 intermittent circuit low.
