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Home >> Lexus >> 2008 >> LX 570 >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Networking >> Can Communication System >> DTC U0127 Lost Communication with Tire Pressure Monitor Module >> Inspection Procedure
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

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 (TIRE PRESSURE WARNING ECU BRANCH WIRE) 
    1. Disconnect the L10 tire pressure warning 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
    L10-6 (CANP) - L10-12 (CANN) Engine switch off 54 to 69 Ω

    NG: REPAIR OR REPLACE TIRE PRESSURE WARNING ECU BRANCH WIRE OR CONNECTOR (CANP, CANN) 

    Fig 1: Identifying Terminal CANP & CANN Of Tire Pressure Warning ECU Connector
    G05639446Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING 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 L10 tire pressure warning 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
      L10-7 (GND) - Body ground Always Below 1 Ω
    4. Measure the voltage according to the value(s) in the table below.
    Fig 2: Identifying Terminal IG & GND Of Tire Pressure Warning ECU Connector
    G05639447Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Standard Voltage 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Switch Condition Specified Condition
    L10-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE TIRE PRESSURE WARNING ECU  (See REMOVAL )

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