P1121

P1121 - Accelerator Pedal Position Sensor Range/Performance Problem

CIRCUIT DESCRIPTION

DTC Detecting Condition:

Accelerator pedal position sensor is mounted on the throttle body and it has 2 sensors to detects the accelerator position and a malfunction of the accelerator positions own. The accelerator pedal position sensor is connected with the accelerator pedal by the accelerator wire and the voltage applied to terminals VPA and VPA2 of the ECM changes between 0 V and 5 V in proportion to the opening angle of the accelerator pedal.
The ECM judges the current opening angle of the accelerator pedal by these signals input from terminals VPA and VPA2 and the ECM controls the throttle motor based on these signals.
If this DTC is stored, the ECM shuts down the power for the throttle motor and the magnetic clutch, and the throttle valve is fully closed by the return spring.
However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable.

Wiring Diagram:

INSPECTION PROCEDURE

HINT: Read freeze frame data using LEXUS hand-held tester or OBD II scan tool. Because freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

Replace accelerator pedal position sensor.