Circuit Description

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Throttle motor is operated by the ECM and it opens and closes the throttle valve. The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the throttle body. It provides feedback to the ECM to control the throttle motor in order to adjust the throttle valve opening angle properly in response to driving condition. If either DTC is stored, the ECM shuts down the power for the throttle motor, and throttle valve is fully closed by the return spring. DTC detection condition is when throttle control motor output duty is greater than 80 percent and current is less than .5 amps for 2 seconds, throttle control motor circuit is greater than 10 amps, or throttle control motor current is greater than 7 amps for more than .6 seconds. See Fig 1. Possible causes are:

Open or short in throttle motor circuit.
Faulty throttle control motor.
Faulty ECM.

Fig 1: Identifying Throttle Actuator Control Motor Circuits