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Home › Lexus › 2002 › ES 300 › Repair and Diagnosis › External Pages › Different car › Section 306 (LEXUS Navigation System - Diagnosis) › Navigation Screen Not Stabilized (Synchronous Error) › Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT NAVIGATION ECU (+B, ACC, GND) 
    1. Remove the navigation ECU with connectors with still connected.
    2. Check voltage.
      1. Measure voltage between terminals +B, ACC and GND of navigation ECU at each conditions, as shown in the chart.

        Standard: 

        NAVIGATION ECU TERMINALS +B, ACC AND GND STANDARD VOLTAGE

        Terminal Condition Voltage (v)
        +B <=> GND Constant 10-14V
        ACC <=> GND Turn ignition switch ACC 10-14V
    3. Check continuity.
      1. Check that the continuity exists between terminal GND of navigation ECU and body ground.

        Standard: Continuity exists. 

        Fig 1: Inspection Navigation ECU (+B, ACC, GND)
        G03372695Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: Go to next step. 
  2. INSPECT NAVIGATION ECU (SYNC, VR, VG) 
    1. Check continuity.
      1. Check that the continuity exists between each terminals, as shown in the chart.

        Standard: 

        TERMINAL SPECIFIED CONDITION

        Terminal Condition Specified condition
        VR <=> Body ground Constant Continuity
        VG <=> Body ground Constant Continuity
    2. Check signal waveform.
      1. Using an oscilloscope, check signal waveform between terminals SYNC and GND of navigation ECU.
        Fig 2: Inspect Navigation ECU (SYNC, VR, VG)
        G03372696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        ITEM CONTENTS

        Item Contents
        Tool setting 500mV/DIV, "MU"s/DIV
        Condition Navigation display is displayed

        HINT:

        Signal wave from is shown in the chart.

        Fig 3: Oscilloscope Signal Waveform Graph
        G03372697Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: CHECK AND REPLACE NAVIGATION RECEIVER ASSY 
    2. OK: Go to next step. 
  3. INSPECT NAVIGATION RECEIVER ASSY (SYNC, VR, VG) 
    1. Check continuity.
      1. Check that the continuity exists between each terminals, as shown in the chart.

        Standard: 

        TERMINAL SPECIFIED CONDITION

        Terminal Condition Specified condition
        VR <=> Body ground Constant Continuity
        VG <=> Body ground Constant Continuity
    2. Check signal waveform.
      1. Using an oscilloscope, check signal waveform between terminals SYNC and GND of radio receiver assy.
        Fig 4: Inspecting Navigation Receiver Assy (SYNC, VR, VG)
        G03372698Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        ITEM CONTENTS

        Item Contents
        Tool setting 500 mV/DIV, 10 "MU"s/DIV
        Condition Navigation display is displayed

        HINT:

        Signal wave from is shown in the chart.

        Fig 5: Oscilloscope Signal Waveform Graph
        G03372699Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: CHECK AND REPLACE NAVIGATION RECEIVER ASSY 
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