Possible causes

– Faulty Accelerator Pedal Position Sensor
– Accelerator Pedal Position Sensor harness is open or shorted
– Accelerator Pedal Position Sensor circuit poor electrical connection

Tech notes

For Hybrid Lexus Vehicles P1121 = Coolant Flow Control Valve Position Sensor Circuit Stuck. See: P1121 Lexus

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1121 LEXUS Description

Accelerator pedal position sensor is mounted on the throttle body and it has the 2 sensors to detects the accelerator position and a malfunction of the accelerator position