Monitor Description

The ECM controls the engine water pump assembly by calculating the necessary amount of coolant flow based on engine coolant temperature, engine speed and vehicle speed information. The speed of the engine water pump assembly is controlled steplessly using a duty cycle signal sent from the ECM. This optimal control enhances warm-up performance and reduces cooling losses, thus reducing the specific fuel consumption of the engine. The ECM monitors the speed of the engine water pump assembly and stores a DTC when it determines that the engine water pump assembly rotates excessively based on the fact that the actual speed is higher than the target for a certain amount of time. (However, the MIL will not illuminate.)