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Home >> Lexus >> 2002 >> IS 300 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 8 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0121: Throttle Position (TP) Sensor "A" Circuit Range/Performance Fault >> Circuit Description
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Circuit Description

WARNING: This page is about a different car, the 2002 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

The TP sensor is a dual variable resistor sensor that monitors throttle opening and TP sensor malfunction. Based on TP sensor signal, ECM determines vehicle driving condition and uses and uses throttle control motor to set throttle angle accordingly. DTC is set when VTA and VTA2 circuit voltage on TP sensor is out of range for 2 seconds. Possible cause is; faulty TP sensor.