Navigation ECU Power Source Circuit: Procedure

1. Disconnect the H4 display and navigation module display connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Measure the resistance according to the value(s) in the table below.
   STANDARD RESISTANCE
   
   

   Tester Connection	Condition	Specified Condition
   H4-10 (GND1) - Body ground	Always	Below 1 Ω

3. Measure the voltage according to the value(s) in the table below.
   STANDARD VOLTAGE
   
   

   Tester Connection	Condition	Specified Condition
   H4-1 (+B1) - H4-10 (GND1)	Always	11 to 14 V
   H4-3 (IG) - H4-10 (GND1)	Engine switch on (IG)	11 to 14 V
   H4-2 (ACC) - H4-10 (GND1)	Engine switch on (ACC)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Display and Navigation Module Display)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   2