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Home >> Lexus >> 2004 >> GS 430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine (3UZ-FE) - Diagnostics >> Circuit Inspection >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. Check voltage between terminals +B and E1 of ECM connector. 

    PREPARATION: 

    1. Remove the engine room ECM cover.
    2. Turn the ignition switch ON.

    CHECK: 

    Measure the voltage between terminals +B and E1 of the ECM connector.

    Fig 1: Checking Voltage Between Terminals +B & E1 Of ECM Connector
    G01488681Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Voltage: 9 to 14 V 

    1. OK: Proceed to next circuit inspection shown in the Problem symptoms table (See  PROBLEM SYMPTOMS TABLE  ).  
    2. NG: Go to next step 
  2. Check for open in harness and connector between terminal E1 of ECM and body ground (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  
    1. NG: Repair or replace harness or connector. 
    2. OK: Go to next step 
  3. Check voltage between terminal IGSW of ECM connector and body ground. 

    PREPARATION: 

    1. Remove the engine room ECM cover.
    2. Turn the ignition switch ON.

    CHECK: 

    Measure the voltage between terminal IGSW of the ECM connector and body ground.

    Fig 2: Checking Voltage Between Terminal IGSW Of ECM Connector & Body Ground
    G01488682Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Voltage: 9 to 14 V 

    1. OK: Go to step   6 . 
    2. NG: Go to next step 
  4. Check IGN fuse. 

    PREPARATION: 

    Remove the IGN fuse from the driver side J/B.

    CHECK: 

    Check the continuity of the IGN fuse.

    Fig 3: Identifying IGN Fuse
    G01488683Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Continuity 

    1. NG: Check for short in all harness and components connected to IGN fuse. 
    2. OK: Go to next step 
  5. Check ignition switch (See  INSPECTION  ).  
    1. NG: Replace ignition switch. 
    2. OK: Go to next step 

      Check and repair harness and connector between battery and ignition switch, and ignition switch and ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  

  6. Check voltage between terminal MREL of ECM connector and body ground. 

    PREPARATION: 

    1. Remove the engine room ECM cover.
    2. Turn the ignition switch ON.

    CHECK: 

    Measure the voltage between terminal MREL of the ECM connector and body ground.

    Fig 4: Checking Voltage Between Terminal MREL Of ECM Connector & Body Ground
    G01488684Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Voltage: 9 to 14 V 

    1. NG: Replace ECM (See  ENGINE CONTROL MODULE (ECM)  ).  
    2. OK: Go to Next Step 
  7. Check EFI fuse of engine room No. 1 R/B. 
    1. NG: Check for short in all harness and components connected to EFI fuse. 
    2. OK: Go to next step 
  8. Check EFI main relay (Marking: EFI) (See  EFI MAIN RELAY  ).  
    1. NG: Replace EFI main relay. 
    2. OK: Go to next step 
  9. Check for open and short in harness and connector between terminal MREL of ECM and body ground (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  
    1. NG: Repair or replace harness or connector. 
    2. OK: Go to next step 

      Check and repair harness or connector between EFI fuse and battery (see  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  

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