Inspection Procedure

WARNING: This page is about a different car, the 2003 Toyota Camry. 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 with still connected.
  
  Fig 1: Measuring Voltage Between Terminals +B, ACC And GND Of Navigation ECU
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check voltage.
  1. Measure voltage between terminals +B, ACC and GND of navigation ECU at each conditions, as shown in the chart.
  Standard:
  
  Fig 2: Navigation ECU Connector Terminals Voltage Check Reference Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check continuity.
  1. Check that the continuity exists between terminal GND of navigation ECU and body ground.
    Standard: Continuity exists.
1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK : CHECK AND REPLACE NAVIGATION ECU