(b) - Check The Master Warning Light

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If the master warning light does not come on, suspect a burnt fuse, burnt bulb, or open in wiring harness.

Fig 1: Identifying Master Warning Light

Turn the ignition switch ON and confirm that the master warning light comes on.
When the "READY" light is ON, the master warning light should go off.
If the lamp remains on, the diagnosis system has detected a malfunction in the system or the message such as "When you park your car, make sure you shift to Park (P)." and "The batteries will not charge if the shifter is N" appears on the multi-information display.

Fig 2: Identifying Ready Light
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Since DTC may be stored even though the lamp is OFF, be sure to check DTC.