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Home >> Lexus >> 2009 >> LS 600hL >> Repair and Diagnosis >> External Pages >> Different car >> Section 174 (Can Communication - Stop Mode Diagnostics, Bus Line Troubleshooting) >> Skid Control ECU Communication Stop Mode >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

Operating the power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.
    CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation.
    NOTE:
    • After the power switch is turned OFF, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the power switch OFF, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.
    • When disconnecting the cable, some systems need to be initialized after the cable is reconnected (see INITIALIZATION ).
  2. CHECK FOR OPEN IN CAN BUS WIRE (SKID CONTROL ECU BRANCH WIRE) 
    1. Disconnect the A19 and A21 skid control ECU connectors
    2. Measure the resistance according to the value (s) in the table below

      Standard resistance 

    RESISTANCE SPECIFICATION

    Tester Connection Switch Condition Specified Condition
    A21-9 (CANH) - A21-8 (CANL) Power switch OFF 54 to 69 Ω
    Fig 1: Identifying A21 ECU Connector Terminals
    G04953626Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE SKID CONTROL ECU BRANCH WIRE OR CONNECTOR (CANH, CANL) 

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BATTERY AND BODY GROUND) 
    Fig 2: Identifying A19 And A21 ECU Connector Terminals
    G04953627Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Connect the cable to the negative (-) battery terminal
      NOTE: When disconnecting the cable, some systems need to be initialized after the cable is reconnected (see INITIALIZATION ).
    2. Disconnect the A19 and A21 skid control ECU connectors.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      A19-1 (GND) - Body ground Always Below 1 Ω
      A21-1 (GND4) - Body ground Always Below 1 Ω
    4. Measure the voltage according to the value (s) in the table below.

    Standard voltage 

    VOLTAGE SPECIFICATION

    Tester Connection Switch Condition Specified Condition
    A19-43 (+BI1) - Body ground Always 11 to 14 V
    A21-38 (+BI2) - Body ground Always 11 to 14 V
    A19-29 (+BI3) - Body ground Always 11 to 14 V
    A21-22 (+BI4) - Body ground Always 11 to 14 V
    A19-46 (IG1) - Body ground Power switch ON (IG) 11 to 14 V
    A21-46 (IG2) - Body ground Power switch ON (IG) 11 to 14 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE SKID CONTROL ECU  (See REMOVAL )