Diagnosis System

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 clearing the DTCs, activating indicators and checking the data list.

2. The diagnosis information of the steering lock ECU is transmitted to the tester via the certification ECU as the steering lock ECU is not connected to the BEAN.
3. Check the DLC3.

   The certification ECU follows the 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 Connector Terminal

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   TERMINALS SPECIFIED CONDITION
   
   

   Symbols (Terminals No.)	Terminal Description	Condition	Specified Condition
   SIL(7) - SG (5)	Bus "+" line	During communication	Pulse generation
   CG(4) - Body ground	Chassis ground	Always	Below 1 Ω
   SG(5) - Body ground	Signal ground	Always	Below 1 Ω
   BAT(16) - Body ground	Battery positive	Always	11 to 14 V

HINT:

If the display shows a communication error message after connecting the hand-held tester cable to the DLC3 and turning the engine switch on (IG), 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 listed in the tester's operator's manual.

1. The steering lock ECU blinks the LED indicator of the engine switch when any of the following problems occurs in the system.
   Fig 2: Identifying Indicator Light

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   Fig 3: Trouble Shooting Table

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1. The steering lock ECU displays a warning on the combination meter when any of the following problems occurs in the system.
   Fig 4: Trouble Shooting Table

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002