DTC P2610 ECM / PCM Internal Engine Off Timer Performance: Description
WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.
The ECM monitors some systems using the soak timer, which is built into the ECM and measures the amount of time that the ignition switch is OFF. To ensure the accuracy of the monitor values, the soak timer measures the time from when the ignition switch is turned to OFF, until the time when each monitor runs. This allows the engine to cool, which stabilizes the EVAP pressure and the engine temperature conditions. When a certain time has elapsed, the ECM turns on.
HINT:
The soak time (the amount of time the ignition switch is OFF) differs according to the DTC monitor.