2007 Lexus GS 450hFACTORY OEM SERVICE PROCEDURE

Test Mode Procedure

  1. WARNING LIGHT AND INDICATOR LIGHT BULB CHECK 
    1. Release the parking brake.
      NOTE: When releasing the parking brake, set chocks to hold the vehicle for safety.

      HINT:

  2. SENSOR SIGNAL CHECK BY TEST MODE (SIGNAL CHECK) (WHEN USING INTELLIGENT TESTER) 
    1. When having replaced the skid control ECU and/or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor.

      HINT:

      • If the power switch is turned from ON (IG) to ON (ACC) or OFF during Test Mode (signal check), DTCs of the signal check function will be erased.
      • During Test Mode (signal check), the skid control ECU records all DTCs of the signal check function. By performing the Test Mode (signal check), the codes are erased if normality is confirmed. The remaining codes are the codes where an abnormality was found.
    2. Procedure for Test Mode.
      1. Turn the power switch OFF.
      2. Connect the intelligent tester (with CAN VIM) to the DLC3.
        Fig 2: Connecting Intelligent Tester To DLC3
        G05298631Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      3. Check that the steering wheel is centered and move the shift lever to the P position.
      4. Turn the power switch ON (IG).
      5. Set the intelligent tester to Test Mode (select "Signal Check").

        HINT:

        Refer to the intelligent tester operator's manual for further details.

      6. Check that the ABS and brake control warning lights blink and "VSC TEST MODE" is indicated on the multi-information display (Test Mode).

        HINT:

        If the ABS and brake control warning lights do not blink, inspect the TS and CG terminal circuit, ABS warning light circuit and/or brake control warning light (multi-information display) circuit.

        Fig 3: Identifying ABS And Brake Control Warning Lights Blinking Pattern
        G05297011Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      7. Check the ABS sensor.

        HINT:

        Make sure that the ABS warning light is blinking in Test Mode before performing the check.

        Fig 4: ABS Warning Light Blinking Pattern In Test Mode
        G04977997Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. ACCELERATION SENSOR CHECK (WHEN USING INTELLIGENT TESTER) 
    1. Keep the vehicle stationary on a level surface for 1 second or longer.

      HINT:

      The acceleration sensor check can be performed with the following master cylinder pressure sensor check.

  4. MASTER CYLINDER PRESSURE SENSOR CHECK (WHEN USING INTELLIGENT TESTER) 
    1. Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly and continuously depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more for 1 second.
    2. Check that the ABS warning light stays on for 3 seconds.

      HINT:

      • Ensure that the ABS warning light comes on.
      • While the ABS warning light stays on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more.
      • The ABS warning light comes on for 3 seconds every time brake pedal operation above is performed.
  5. SPEED SENSOR CHECK (WHEN USING INTELLIGENT TESTER) 
    1. Check the backward signal.
      1. Drive the vehicle in reverse for more than 1 second at the speed of 3 km/h (2 mph) or higher.

        HINT:

        Drive the vehicle in reverse and check the speed sensor signal. The signal check cannot be completed if the vehicle speed is 45 km/h (28 mph) or higher.

    2. Check the forward signal.
      1. Drive the vehicle straight ahead.

        Drive the vehicle at a speed of 45 km/h (28 mph) or higher for several seconds and check that the ABS warning light goes off.

        HINT:

        The signal check may not be completed if the vehicle has its wheels spun.

    3. Stop the vehicle.
      NOTE:
      • Before performing the speed sensor signal check, complete the acceleration sensor and master cylinder pressure sensor checks.
      • The speed sensor signal check may not be completed if the speed sensor signal check is started while turning the steering wheel or spinning the wheels.
      • After the ABS warning light goes off and if the vehicle speed exceeds 80 km/h (50 mph), a signal check code will be stored again. Accelerate or stop the vehicle before the speed reaches 80 km/h (50 mph).
      • If the signal check has not been completed, the ABS warning light blinks while driving and the ABS system does not operate.

      HINT:

      When the signal check has been completed, the ABS warning light goes off while driving, and blinks in the Test Mode pattern while the vehicle is stationary.

      1. Check the VSC sensor.

        Perform the check after checking that the brake control warning light blinks and that "VSC TEST MODE" is indicated on the multi-information display.

        Fig 5: Brake Control Warning Light Blinking Pattern
        G05305914Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. YAW RATE SENSOR CHECK (WHEN USING INTELLIGENT TESTER) 
    1. Check the zero point voltage of the yaw rate sensor.
      1. Keep the vehicle stationary on a level surface for 1 second or longer.
    2. Check the output of the yaw rate sensor and the direction of the steering angle sensor.
      1. Move the shift lever from P to the D position and drive the vehicle at a speed of approximately 5 km/h (3 mph), turn the steering wheel either to the left or right 90° or more until the vehicle makes a 180° turn.
        Fig 6: Checking Output Of Yaw Rate Sensor
        G05305915Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Stop the vehicle and move the shift lever to the P position. Check that the skid control buzzer sounds for 3 seconds.

        HINT:

        • If the skid control buzzer sounds, the signal check is completed normally.
        • If the skid control buzzer does not sound, check the skid control buzzer circuit, then perform the signal check again.
        • If the skid control buzzer still does not sound, there may be a malfunction in the yaw rate sensor, so check the DTC.
        • At the end of the 180° turn, the direction of the vehicle should be within 180° +-5° of its start position.
        • Do not spin the wheels.
        • Do not turn the power switch OFF while turning.
        • Do not move the shift lever to the P position while turning, but change in the vehicle speed, stopping, or driving in reverse is possible.
        • Complete the turn within 20 seconds.
  7. END OF SENSOR CHECK (WHEN USING INTELLIGENT TESTER) 
    1. If the sensor check is completed, the ABS warning light blinks (Test Mode) when the vehicle stops, and the ABS warning light goes off when the vehicle is driving.
      NOTE:
      • When the yaw rate sensor, acceleration sensor, speed sensor and master cylinder pressure sensor checks are finished, all the sensor checks are completed.
      • If all the sensor checks are not completed, the ABS warning light blinks even while the vehicle is driving and the ABS does not operate.
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.