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Home › Lexus › 2004 › IS 300 Base, Automatic › Repair and Diagnosis › Engine Performance › Engine Control System - Diagnosis › Circuit Inspection › DTC P1126: Magnetic Clutch Circuit › Inspection Procedure

Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

  1. Check magnetic clutch circuit. 

    When using hand-held tester: 

    PREPARATION: 

    1. Connect the hand-held tester to the DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main switch ON.

    CHECK: 

    Read the magnetic clutch current valve on the hand-held tester.

    OK: 

    1. Current: 0.8 to 1.0 A 

    When not using hand-held tester: 

    PREPARATION: 

    1. Connect an oscilloscope between terminals CL+ and CL- of the ECM connector.
    2. Start the engine.

    CHECK: 

    Check the waveform between terminals CL+ and CL- of the ECM connector while the engine is idling.

    Fig 1: Checking CL Signal Waveform
    G01496445Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    The current waveform is as shown. 

    1. NG: Go to step   4 . 
    2. OK: Go to next step. 
  2. Check magnetic clutch. 

    PREPARATION: 

    Disconnect the throttle control motor together with the magnetic clutch connector.

    CHECK: 

    Measure the resistance between terminals 3 and 4 of the throttle control motor with the magnetic clutch.

    Fig 2: Measuring Resistance Between Terminals 3 & 4
    G01496446Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Resistance: 4.2 to 5.2 Ω at 20°C (68°F) 

    1. NG: Replace throttle control motor with magnetic clutch (See REPLACEMENT ).
    2. OK: Go to next step. 
  3. Check for open and short in harness and connector between magnetic clutch and ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    1. NG: Repair or replace harness or connector. 
    2. OK: Go to next step. 
  4. Check operation of magnetic clutch. 

    CHECK: 

    1. Clear the DTC.
    2. Perform the following steps and check the DTC.
      1. Turn the ignition switch ON.
      2. Start the engine.
      3. Turn the ignition switch OFF and wait 3 seconds.
      4. Turn the ignition switch ON

    OK: 

    DTC P1126 is not stored. 

    1. NG: Replace throttle control motor with magnetic clutch (See  REPLACEMENT  ) 
    2. OK: Go to next step. 

      Replace ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 

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