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.

REMOVE OPTIONAL PARTS (CELLULAR MOBILE TELEPHONE)
1. Remove optional parts (Cellular mobile telephone).
  1. Disconnect the cellular mobile telephone wire harness.
  2. Connect the wire harness of the navigation system so that the cellular mobile telephone is not linked.
2. Check that the malfunction disappears when operating the navigation system again.
  
  Fig 1: Cellular Phone Malfunction Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. B: CHECK AND REPLACE TELEPHONE COMPUTER AND WIRE HARNESS
2. A: Go to next step.
SERVICE CHECK MODE (NAVIGATION ECU)
1. Perform service check.
  1. Start the diagnosis system and read check result for gateway ECU.
  Result:
  
  Fig 2: Check Result Table For Gateway ECU Diagnosis
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. B: CHECK AND REPLACE MULTI-DISPLAY (CRT DISPLAY) DISPLAY
2. C: Go to next step.
  TROUBLESHOOT FOR EACH DIAGNOSIS
3. A: Go to next step.
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 GND of navigation ECU under each condition, as shown in Fig 3.
    
    Fig 3: +B, ACC and GND Terminal Voltages - Navigation ECU
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  Voltage:
  
  Fig 4: Measuring Voltage Between Connector Terminals +B, ACC & GND Of Navigation ECU
  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: CHECK AND REPLACE NAVIGATION ECU
2. OK: Go to next step.
CHECK HARNESS OR CONNECTOR (BETWEEN NAVIGATION ECU AND STEREO COMPONENT AMPLIFIER ASSY)
1. Disconnect the "N4" connector from the navigation ECU.
2. Disconnect the "S23" connector from the stereo component amplifier.
3. Check continuity.
  1. Check the continuity between navigation ECU and stereo component amplifier.
    
    Fig 5: Continuity Specification Table - Navigation ECU And Stereo Component Amplifier Assy
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  Standard:
  
  Fig 6: Identifying Connector Terminals Of Navigation ECU & Stereo Component Amplifier
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: Go to next step.
INSPECT INSTRUMENT CLUSTER FINISH PANEL SUB-ASSY CENTER (WIRE HARNESS)
1. Remove instrument cluster finish panel sub-assy center.
2. Check wire harness.
1. NG: CHECK AND REPLACE INSTRUMENT CLUSTER FINISH PANEL SUB-ASSY CENTER
2. OK: Go to next step.
CHECK AND REPLACE MULTI-DISPLAY JUNCTION BLOCK
1. Check multi-display junction block.
  1. Check malfunction disappears when known good multi-display junction block is installed.
    
    Fig 7: Multi-Display Junction Block Malfunction Table
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. B: REPLACE MULTI-DISPLAY JUNCTION BLOCK
2. A: Go to next step.
CHECK NETWORK GATEWAY ECU (BATT, ACC, IG, GND)
1. Remove the network gateway ECU with connectors still connected.
2. Check voltage.
  1. Turn ignition switch ON.
  2. Measure voltage between terminals BATT, ACC, IG and GND of network gateway ECU under each condition, as shown in Fig 9.
    
    Fig 8: Measuring Voltage Between Terminals BATT, ACC, IG & GND Of Network Gateway ECU
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  Voltage:
  
  Fig 9: BATT, ACC, IG & GND Terminal Specification Table - Network Gateway ECU
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check continuity.
  1. Check continuity exists between terminal GND of network gateway ECU and body ground.
  Standard: Continuity exists
1. OK: CHECK AND REPLACE NETWORK GATEWAY ECU
2. NG: Go to next step.
REPAIR OR REPLACE HARNESS OR CONNECTOR