Diagnosis System

DESCRIPTION
1. DIAGNOSTIC SYSTEM
  When troubleshooting a vehicle with a diagnostic system, the only difference from the usual troubleshooting procedure is connecting the hand-held tester to the vehicle and reading various data output from the vehicle's steering lock ECU.
  
  The steering lock ECU records DTCs when the computer detects a malfunction in the computer itself or in its circuits.
  
  To check the DTCs, connect the hand-held tester to the DLC3 on the vehicle. The hand-held tester enables you to erase the DTCs, activate the several actuators and check data list.
2. Check the DLC3.
  The steering lock ECU follows the CAN and ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.
  
  Fig 1: Identifying DLC3 Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Terminal Specified Condition Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  HINT:
  
  If the display shows "UNABLE TO CONNECT TO VEHICLE" after connecting the hand-held tester cable to the DLC3 and turning the ignition switch to the ON position, there is a problem with either the vehicle or tester.
  - If communication is normal when connecting the tester to another vehicle, inspect the DLC3 on the original vehicle.
  - If communication is still not possible when connecting the tester to another vehicle, the problem is probably on the tester itself, so consult the Service Department list the tester's operator's manual.