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Home >> Lexus >> 2003 >> ES 300 >> Repair and Diagnosis >> External Pages >> Different car >> Section 161 (Engine Control System (SFI) (1MZ-FE-3MZ-FE) - Diagnostics) >> ECM Power Source Circuit >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2004 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT ECM (+B VOLTAGE) 
    1. Turn the ignition switch ON.
    2. Measure the voltage of the ECM connectors.

      Standard: 

      ECM CONNECTOR TERMINAL VOLTAGE SPECIFICATION

      Tester Connection Specified Condition
      E6-1 (+B) - E8-1 (E1) 9 to 14 V
      Fig 1: Inspecting ECM (+B Voltage)
      G02900711Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See  PROBLEM SYMPTOMS TABLE  ) 
    2. NG: Go to next step. 
  2. CHECK WIRE HARNESS (ECM - BODY GROUND) 
    1. Disconnect the E8 ECM connector.
    2. Check the resistance of the wire harness side connectors.

      Standard: 

      E8 ECM CONNECTOR VOLTAGE SPECIFICATION

      Tester Connection Specified Condition
      E8-1 (E1) - Body ground Below 1 Ω
      Fig 2: Identifying E8 ECM Connector
      G02900712Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: Go to next step. 
  3. INSPECT ECM (IGSW VOLTAGE) 
    1. Turn the ignition switch ON.
    2. Measure the voltage of the ECM connectors.

      Standard: 

      ECM CONNECTORS VOLTAGE SPECIFICATION

      Tester Connection Specified Condition
      E6-9 (IGSW) - E8-1 (E1) 9 to 14 V
      Fig 3: Identifying E8 And E6 ECM Connector Terminals
      G02900713Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: Go to step   6 
    2. NG: Go to next step. 
  4. CHECK FUSE (IG2) 
    1. Remove the IG2 fuse from the engine room J/B.
    2. Check the resistance of the IG2 fuse.

      Standard: Below 1 Ω 

      Fig 4: Identifying IG2 Fuse In Engine Room J/B
      G02900714Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE FUSE 
    2. OK: Go to next step. 
  5. INSPECT IGNITION OR STARTER SWITCH ASSY 
    1. Check the resistance of the switch terminals shown in the chart below.

      Standard: 

      IGNITION OR STARTER SWITCH TERMINALS RESISTANCE SPECIFICATION

      Switch Condition Tester Connection Specified Condition
      LOCK 6 (IG2) - 7 (AM2) 10 kΩ or higher
      START 6 (IG2) - 7 (AM2) Below 1 Ω
      Fig 5: Identifying Ignition Or Starter Switch Connector Terminals
      G02900715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE IGNITION OR STARTER SWITCH ASSY 
    2. OK: CHECK AND REPAIR HARNESS AND CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM) 
  6. INSPECT ECM (MREL VOLTAGE) 
    1. Turn the ignition switch ON.
    2. Measure the voltage of the ECM connectors.

      Standard: 

      ECM CONNECTORS VOLTAGE SPECIFICATION

      Tester Connection Specified Condition
      E6-8 (MREL) - E8-1 (E1) 9 to 14 V
      Fig 6: Identifying ECM (MREL) Connector Terminals
      G02900716Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE ECM (See  ELECTRONIC CIRCUIT INSPECTION PROCEDURE  ). 
    2. OK: Go to next step. 
  7. CHECK FUSE (EFI) 
    1. Remove the EFI fuse from the engine room J/B.
    2. Check the resistance of the EFI relay.

      Standard: Below 1 Ω 

    1. NG: REPLACE FUSE 
    2. OK: Go to next step. 
  8. INSPECT RELAY (EFI) 
    1. Remove the EFI relay from the engine room J/B.
    2. Check the resistance of the EFI relay.

      Standard: 

      EFI RELAY CONNECTOR TERMINALS RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)
      Fig 7: Checking Resistance Of EFI Relay
      G02900717Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE RELAY 
    2. OK: Go to next step. 
  9. CHECK WIRE HARNESS (EFI RELAY - ECM, EFI RELAY - BODY GROUND) 
    1. Check the wire harness between the EFI relay and ECM.
      1. Remove the EFI relay from the engine room J/B.
      2. Disconnect the E6 ECM connector.
      3. Check the resistance of the wire harness side connectors.

      Standard: 

      EFI RELAY AND ECM CONNECTOR TERMINAL RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      J/B EFI relay terminal 1 - E6-8 (MREL) Below 1 Ω
      J/B EFI relay terminal 1 or E6-8 (MREL) - Body ground 10 kΩ or higher
    2. Check the wire harness between the EFI relay and body ground.
      1. Remove the EFI relay from the engine room J/B.
      2. Check the resistance between the wire harness side connector and body ground.

      Standard: 

      EFI RELAY AND BODY GROUND RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      J/B EFI relay terminal 2 - Body ground Below 1 Ω
      Fig 8: Identifying MREL And EFI Relay Connector Terminals
      G02900718Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. NG: CHECK AND REPAIR HARNESS AND CONNECTOR (TERMINAL +B OF ECM - BATTERY POSITIVE TERMINAL) 
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