With Vehicle Control Module (VCM-A)

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 Vehicle Control Module (VCM-A) 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 volts.

The VCM-A 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 VCM-A thinks the throttle is moving. A problem in the TP sensor 5 volt reference or signal circuits should set either a Diagnostic Trouble Code (DTC) PO122 or DTC P0123. A problem with the TP sensor ground circuit may set DTCs PO123 or PO117. Once a DTC is set, the VCM-A will use an artificial default value for TP sensor and some vehicle performance will return. A high idle may result when either DTC PO122 or DTC PO123 is set. Refer to Diagnostic Trouble Code Charts. Under Computer and Controls/System Diagnosis/Procedures. Testing and Inspection