Circuit Description

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

Throttle motor is operated by ECM and opens and closes throttle valve. Opening angle of throttle valve is detected by throttle position sensor which is mounted on throttle body and provides feedback to ECM. ECM then controls throttle motor to set throttle valve opening angle correctly in response to driving condition. If a DTC is stored, throttle valve is locked at a certain opening angle. Also, electronically controlled throttle operation is cancelled until system returns to normal and ignition switch is turned off.

DTCs are also set when throttle control motor output duty is 80 percent or greater and throttle control motor current is less than .5 amp for 2 seconds. DTC is also set if throttle control motor current is 16 amps or more or throttle control motor circuit is 7 amps or greater for .6 seconds. Possible causes are:

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