Possible causes

– Faulty Throttle Control Motor
– Throttle Control Motor harness is open or shorted
– Throttle Control Motor circuit poor electrical connection

When is the code detected?

Engine Control Module (ECM) detects short both circuits between ECM and throttle control motor.

Symptoms

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

P1128 TOYOTA Description

The throttle control motor is operated by the Engine Control Module (ECM) and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feedback to the ECM to control the throttle control motor to make the throttle valve opening angle properly in response to driving condition.

TOYOTA Technical Service Bulletins for P1128 code