Toyota Corolla Repair Manual: Identification information
The variable valve timing (vvt) system includes the ecm, the oil control valve (ocv) and the vvt controller. The ecm sends a target ”duty–cycle” control signal to the ocv. This control signal, applied to the ocv, regulates the oil pressure supplied to the vvt controller. Camshaft timing co ...
While the engine is being cranked, the battery positive voltage is applied to terminal sta of the ecm. If the ecm detects the starter control signal (sta) while the vehicle is driving, it will conclude that there is a fault in the starter control circuit.