No Shift From 4H To 4L
WARNING: This page is about a different car, the 2002 Toyota Tundra and 2001 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
Faulty touch select high-low switch. VSS inoperative or inaccurate. L4 position switch malfunction. PNP switch malfunction. 4L indicator switch faulty. Transfer shift actuator malfunction. Wiring harness open, shorted or pinched. 4WD ECU malfunction.