Electromagnetic Oil Pump (EMOP) (Not On Hybrid Vehicles)
Electromagnetic oil pump EMOP is located in the gearbox's control system, which is mounted on the front edge of the gearbox. The design of the electromagnetic oil pump is same as that of a linear pressure solenoid. It consists of an electrical coil that controls a hydraulic valve. The solenoid is controlled by a pulsed (PWM) voltage and grounded via the Transmission Control Module (TCM).
The function of the electromagnetic oil pump is to ensure that the correct pressure and flow rate are obtained for the gearbox during the time that the automatic start/stop of the engine is active. This is needed to prevent pressure loss in gearbox. This is done by C1 clutch being active during automatic start/stop, to immediately transfer the torque when the engine restarts. To avoid the C1 clutch slipping while the engine cranks/starts (before the C1 pressure is increased, which is created by the mechanical oil pump), C1 clutch pressure is maintained by the electromagnetic oil pump EMOP.
In the event of a fault on the oil pump, the automatic start/stop function stops working.
The electromagnetic oil pump can be diagnosed by the Transmission Control Module (TCM).