LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2008 >> LX 570 >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Networking >> Can Communication System >> DTC U0327 Software Incompatibility with Vehicle Security Control Module >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

  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 disable the SRS system.
    NOTE:
    • w/ Navigation System:

      After the engine 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 engine 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 (CERTIFICATION ECU BRANCH WIRE) 
    1. Disconnect the E29 certification ECU (smart key ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

    Standard Resistance 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Switch Condition Specified Condition
    E29-27 (CANH) - E29-28 (CANL) Engine switch off 54 to 69 Ω

    NG: REPAIR OR REPLACE CERTIFICATION ECU (SMART KEY ECU) BRANCH WIRE OR CONNECTOR (CANH, CANL) 

    Fig 1: Checking For Open In CAN Bus Wire (Certification ECU Branch Wire)
    G05639455Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - BATTERY AND BODY GROUND) 
    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 E29 certification ECU (smart key ECU) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      E29-17 (E) - Body ground Always Below 1 Ω
    4. Measure the voltage according to the value(s) in the table below.
    Fig 2: Checking Harness And Connector (Certification ECU - Battery And Body Ground)
    G05639456Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Standard Voltage 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Switch Condition Specified Condition
    E29-1 (+B) - Body ground Always 11 to 14 V
    E29-19 (ACC) - Body ground Engine switch on (ACC) 11 to 14 V
    E29-18 (IG) - Body ground Engine switch on (IG) 11 to 14 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE CERTIFICATION ECU ASSEMBLY (SMART KEY ECU)  (See REMOVAL )

scientia non olet · About LEMON Manuals