Monitor Description
WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.
The ECM commands gearshift by turning the shift solenoid valves ON/OFF. When there is an open or short circuit in the shift solenoid valve S2 circuit, the ECM detects the problem and the MIL comes on. Illuminating the MIL, the ECM performs the fail-safe and turns the other functioning shift solenoid valve ON/OFF.
(If an open or short circuit occurs, the ECM stops sending currents to the affected circuit.)