Navigation ECU Communication Error: Procedure

IDENTIFY THE COMPONENT SHOWN BY SUB-CODE
1. Enter the diagnostic mode.
  
  Fig 1: Identifying LAN Monitor Mode
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Press the "LAN Mon" switch to change to "LAN Monitor" mode.
3. Identify the component shown by the sub-code.
  HINT:
  - "110 (multi-display)" is the component shown by the sub-code in the example shown in the illustration.
  - The sub-code will be indicated by its physical address.
  - For the component list, refer to DIAGNOSIS DISPLAY DETAILED DESCRIPTION .
NEXT: Go to next step

CHECK POWER SOURCE CIRCUIT OF COMPONENT SHOWN BY SUB-CODE

Inspect the power source circuit of the component shown by the sub-code.

If the power source circuit is operating normally, proceed to the next step.

COMPONENT TABLE:

Component	Proceed to
Radio receiver (190)	Refer to Radio Receiver Power Source Circuit
Stereo component amplifier (440)	Refer to Stereo Component Amplifier Power Source Circuit
Multi-display (110)	Refer to Multi-display Power Source Circuit

NEXT: Go to next step

INSPECT RADIO RECEIVER

Disconnect the radio receiver connectors.

Fig 2: Identifying Radio Receiver Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard resistance

Tester Connection	Condition	Specified Condition
ATX+ (E69-5) - ATX- (E69-15)	Always	60 to 80 Ω
TX+ (E70-9) - TX- (E70-10)	Always	60 to 80 Ω

NG → REPLACE RADIO RECEIVER

OK: Go to next step

CHECK HARNESS AND CONNECTOR (NAVIGATION ECU - COMPONENT SHOWN BY SUB-CODE)
HINT:
- Start the check from the circuit that is near the component shown by the sub-code first.
- For details of the connectors, refer to TERMINALS OF ECU .
1. Referring to the AVC-LAN wiring diagram below, check the AVC-LAN circuit between the navigation ECU and the component shown by the sub-code.
  1. Disconnect all connectors between the navigation ECU and the component shown by sub-code.
  2. Check for an open or short in the AVC-LAN circuit between the navigation ECU and the component shown by the sub-code.
    OK
    
    There is no open or short circuit.
    
    Fig 3: View Of AVC-LAN Wiring Diagram
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step
REPLACE COMPONENT SHOWN BY SUB-CODE
1. Replace the component shown by the sub-code with a normal one and check if the same problem occurs again.
  OK
  
  Same problem does not occur.
NG → REPLACE NAVIGATION ECU

OK → END