2008 Lexus IS FFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND) 
    1. Disconnect the TCM connectors.
    2. Turn the engine switch off
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      A58-2 (E1) - Body ground Always Below 1 Ω
      4. Fig 1: Identifying Terminal E1 Of TCM Connector
      G05750797Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  2. CHECK HARNESS AND CONNECTOR (BATTERY - TCM) 
    1. Disconnect the TCM connectors.
    2. Turn the engine switch on (IG)
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A58-5 (+B) - Body ground Engine switch on (IG) 11 to 14 V
      4. Fig 2: Identifying Terminal Of TCM Connector
      G05750798Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM)  (See ECM POWER SOURCE CIRCUIT )

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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