RAV4, Sienna, Tacoma, Tundra Without Tachometer & 4Runner

Disconnect low oil pressure switch connector. See OIL PRESSURE SWITCH LOCATION  table. Using a jumper wire, connect low oil pressure switch connector terminal to ground. Turn ignition switch to ON position. Low oil pressure warning light should turn on. If low oil pressure warning light is off, check bulb or inspect wiring harness.