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Home >> Lexus >> 2004 >> IS 300 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 53 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0121: Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance Fault >> Circuit Description
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Circuit Description

WARNING: This page is about a different car, the 2003 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

The TP sensor is a 2 variable resistor sensor that monitors throttle opening and TP sensor malfunction. Based on TP sensor signal, ECM determines vehicle driving condition and adjusts throttle position accordingly. DTC is set when VTA and VTA2 circuit voltage on TP sensor is out of range for 2 seconds. Possible cause is: