LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 1996 >> Fleetwood Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0121 - TP Sensor Circuit Insufficient Activity >> Circuit Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit Description

The Throttle Position (TP) sensor is a potentiometer mounted on side of throttle body. TP sensor voltage signal changes relative to throttle blade angle. TP sensor uses a 5-volt reference, a ground and a signal circuit. TP sensor signal voltage should be about 0.6 volt at idle and 4 volts or greater at wide open throttle. PCM compares actual throttle position from the TP sensor to a predicted throttle position value. The predicted value is calculated from engine speed and other inputs. If PCM detects the predicted throttle position is less than the actual TP sensor value, DTC will set.