LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2004 >> GS 430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine (3UZ-FE) - Diagnostics >> Circuit Inspection >> Fuel Pump Control Circuit >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

  1. Connect hand-held tester, and check operation of fuel pump (See  ON-VEHICLE INSPECTION  ).  
    1. OK: Go to step   7 . 
    2. NG: Go to next step 
  2. Check voltage of fuel pump ECU power source. 

    PREPARATION: 

    1. Remove the luggage compartment trim cover (See ENGINE CONTROL MODULE (ECM) ).
    2. Disconnect the fuel pump ECU connector.
    3. Turn the ignition switch ON.

    CHECK: 

    Measure the voltage between terminal 10 of the fuel pump ECU connector and body ground.

    Fig 1: Checking Voltage Between Terminal 10 Of Fuel Pump ECU Connector & Body Ground
    G01488686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Voltage: 9 to 14 V 

    1. NG: Check for open and short in harness and connector between EFI main relay (Marking: EFI) and fuel pump ECU (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  
    2. OK: Go to next step 
  3. Check voltage between terminals 5 and 8 of fuel pump ECU connector. 

    PREPARATION: 

    1. Remove the luggage compartment trim cover (See ENGINE CONTROL MODULE (ECM) ).
    2. Disconnect the fuel pump ECU connector.

    CHECK: 

    Measure the voltage between terminals 5 and 8 of the fuel pump ECU connector when the ignition switch is turned to the START position.

    Fig 2: Checking Voltage Between Terminals 5 & 8 Of Fuel Pump ECU Connector
    G01488687Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Voltage: 3.3 to 4.3 V 

    1. OK: Go to step   5 . 
    2. NG: Go to next step 
  4. Check for open and short in harness and connector between terminal FPC of ECM and terminal 8 of fuel pump ECU, and terminal 5 of fuel pump ECU 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 

      Replace ECM (See  ENGINE CONTROL MODULE (ECM)  ).  

  5. Check fuel pump (See  ON-VEHICLE INSPECTION  ).  
    1. NG: Repair or replace fuel pump. 
    2. OK: Go to next step 
  6. Check for open and short in harness and connector between terminal 7 of fuel pump ECU and fuel pump, and terminal 6 of fuel pump ECU and fuel pump (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  
    1. NG: Repair or replace harness or connector. 
    2. OK: Go to next step 

      Replace fuel pump ECU. 

  7. Check for open and short in harness and connector between terminal DI of ECM and terminal 9 of fuel pump ECU (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).  
    1. NG: Repair or replace harness or connector. 
    2. OK: Go to next step 

      Replace ECM (See  ENGINE CONTROL MODULE (ECM)  ).  

scientia non olet · About LEMON Manuals