LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2003 >> SC 430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P2121: Throttle/Pedal Position Sensor/Switch "D" Circuit Range/Performance >> Circuit Description

Circuit Description

The accelerator pedal position sensor is mounted on the accelerator pedal bracket and it has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor. Voltage applied to pedal terminals VPA and VPA2 of ECM changes between 0-5 volts in proportion to opening angle of the accelerator pedal. VPA is a signal to indicate the actual accelerator pedal opening angle which is used for the engine control, and VPA2 is a signal to indicate the information about the opening angle which is used for detecting a malfunction. ECM judges the current opening angle of the accelerator pedal from these signals input from terminals VPA and VPA2. ECM controls throttle motor based on these signals. If DTCs are stored, throttle valve is locked at a certain opening angle. Electronically controlled throttle operation is cancelled until the system returns to normal and the ignition switch is turned OFF. Possible causes are:

scientia non olet · About LEMON Manuals