Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT NAVIGATION ECU (+B, ACC, GND)
1. Remove the navigation ECU with connectors still connected.
2. Check voltage.
  1. Measure voltage between terminals +B, ACC and GND1 of navigation ECU under each condition, as shown in Fig 1.
    
    Fig 1: Terminals +B, ACC and GND1 Continuity Specification Table - Navigation ECU
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Voltage:
    
    Fig 2: Identifying Terminals +B, ACC & GND1 Of Navigation ECU
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check continuity.
  1. Check that the continuity exists between terminal GND1 of navigation ECU and body ground.
    Standard: Continuity exists.
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: Go to next step.
CHECK AND REPLACE NAVIGATION ECU