Monitor Description
WARNING: This page is about a different car, the 2009 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.
5 hours after the ignition switch is turned to OFF, the soak timer activates the ECM to begin the EVAP system monitor. While the engine is running, the ECM monitors the synchronization of the soak timer and the CPU clock. If these two are not synchronized, the ECM interprets this as a malfunction, illuminates the MIL and sets the DTC (2 trip detection logic).