Circuit Description

The ETCS (Electronic Throttle Control System) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (less than 4 V), the ECM determines that there is a malfunction in the ETCS and cuts off the current to the throttle actuator.

When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the throttle actuator is cut. If repairs are made and the system returns to normal, turn the ignition switch to OFF. The ECM then allows the current to flow to the throttle actuator so that it can be restarted.

HINT:

The ETCS does not use a throttle cable.

Fig 1: Throttle Actuator Control Motor Current Range/Performance Circuit Diagram (DTC P2118)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig 2: DTC Trouble Detection Chart (DTC P2118)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.