Propulsion System OFF

The engine control module (ECM) wake-up timer, which is located in the Hybrid Powertrain Control Module 2, activates the ECM at three predetermined times so that leak detection can occur. This is where the EVAP leak detection pump hardware is used. The ECM uses several tests to determine if the EVAP system is leaking or restricted. These tests execute with the engine OFF at 5, 7, or 9.5 hours after the vehicle has been shut OFF. These soak times allow the fuel temperature and pressure to stabilized.