LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2008 >> GX 470 >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control >> Vehicle Stability Control System >> Test Mode Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Mode Procedure

  1. TEST MODE (SIGNAL CHECK) PROCEDURE (SST CHECK WIRE) 

    When having replaced the master cylinder solenoid and/or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor (See CALIBRATION  ).

    HINT:

    • If the ignition switch is turned from the ON to the ACC or LOCK position 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 test mode (Signal Check) function. By performing the test mode (Signal Check), the codes are erased if normality is confirmed. The codes left over are the codes where an abnormality was found.
    1. Turn the ignition switch off.
    2. Check that the steering wheel is in the straight-ahead position and move the shift lever to the P position.
    3. Using SST, connect terminals TS and CG of the DLC3.

      SST 09843-18040 

    4. Turn the ignition switch to the ON position.
      Fig 1: Identifying DLC3 Connector Terminals
      G04832156Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Check that the ABS and VSC TRAC warning lights blink in test mode.

      HINT:

      If the ABS and VSC TRAC warning lights do not blink, inspect the TS and CG terminal circuit and the ABS and VSC TRAC warning light circuits.

      TROUBLE AREA CHART

      Trouble Area See procedure
      TS and CG terminal circuit TS AND CG TERMINAL CIRCUIT 
      ABS warning light circuit ABS WARNING LIGHT REMAINS ON  or ABS WARNING LIGHT DOES NOT COME ON 
      VSC TRAC warning light circuit VSC TRAC WARNING LIGHT REMAINS ON  or VSC TRAC WARNING LIGHT DOES NOT COME ON 
      Fig 2: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    6. Start the engine.
    7. Using a check wire, perform the ABS sensor (acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch, L4 detection switch and speed sensor) and VSC sensor (yaw rate sensor and downhill assist control operation switch) signal checks in test mode (ABS sensor: See procedure "A" to "F", VSC sensor: See procedure "G" to "I").
  2. ACCELERATION SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "A") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Keep the vehicle in a stationary condition on a level surface for 1 second or more.
      Fig 3: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. MASTER CYLINDER PRESSURE SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "B") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more for 1 second or more.
      Fig 4: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • At this time, the ABS warning light stays on for 3 seconds.
      • 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 the brake pedal operation above is performed.
  4. CENTER DIFF. LOCK DETECTION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "C") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the center diff. lock switch.
      1. Push the center diff. lock switch on to lock the center differential.
      2. Push the center diff. lock switch off to unlock the center differential.
        Fig 5: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. L4 DETECTION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "D") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the transfer indicator (L4) switch.
      1. Turn the H-L switch to the L position to put the vehicle in L4 mode.
      2. Turn the H-L switch to the H position to put the vehicle in H4 mode.
        Fig 6: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. SPEED SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "E") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the backward signal.
      1. Drive the vehicle in reverse for more than 1 second at 3 km/h (2 mph) or higher.

        HINT:

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

        Fig 7: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the forward signal.
      1. Drive the vehicle straight forward.

        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 or the steering wheel turned during this check.

    4. Stop the vehicle.
      NOTE:
      • Before performing the speed sensor signal check, complete the acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch and L4 detection switch signal 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, if the vehicle speed exceeds 80 km/h (50 mph), signal check code will be stored again. Decelerate or stop 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 stationary.

  7. READ DTC OF ABS SENSOR (SST CHECK WIRE) (Procedure "F") 
    1. Using SST, connect terminals TC and CG of the DLC3.

      SST 09843-18040 

    2. Read the number of blinks of the ABS warning light.

      HINT:

      • See the list of DTC (See procedure "J").
        Fig 8: Identifying DLC3 Connector Terminals
        G04832160Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • If every sensor is normal, the normal system code is output. (A cycle of 0.25 second ON and 0.25 second OFF is repeated.)
      • If more than 1 malfunction is detected at the same time, the lowest numbered code will be displayed first.
        Fig 9: Identifying Blinking Pattern
        G04965392Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. After the check, disconnect the SST from terminals TC and CG of the DLC3.
  8. YAW RATE SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "G") 
    1. Check that the VSC TRAC warning light is blinking in test mode.
    2. Check the zero point voltage of the yaw rate sensor.
      1. Keep the vehicle in a stationary condition on a level surface for 1 second or more.
        Fig 10: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the output of the yaw rate sensor and the direction of the steering angle sensor.
      1. Shift the shift lever to the D position and drive the vehicle at a vehicle 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.
      2. Stop the vehicle and shift the shift lever to the P position. Check that the skid control buzzer sounds for 3 seconds.
        Fig 11: Identifying Start And End Position
        G04949577Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        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 (See SKID CONTROL BUZZER CIRCUIT  ), then perform the signal check again
        • If the skid control buzzer still will not sound, there is a malfunction in the yaw rate sensor, so check the DTC.
        • Drive the vehicle in a 180° circle. At the end of the turn, the direction of the vehicle should be within 175 to 185° of its start position.
        • Do not spin the wheels.
  9. DOWNHILL ASSIST CONTROL OPERATION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "H") 
    1. Check that the VSC TRAC warning light is blinking in test mode.
    2. Check the downhill assist control switch.
      1. Push the downhill assist control switch on.
      2. Push the downhill assist control switch off.
        Fig 12: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  10. READ DTC OF VSC SENSOR (SST CHECK WIRE) (Procedure "I") 
    1. Using SST, connect terminals TC and CG of the DLC3.

      SST 09843-18040 

    2. Read the number of blinks of the VSC TRAC warning light.
      Fig 13: Identifying DLC3 Connector Terminals
      G04832160Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • See the list of DTC (See procedure "J").
      • If every sensor is normal, the normal system code is output. (A cycle of 0.25 second ON and 0.25 second OFF is repeated.)
      • If more than 1 malfunction is detected at the same time, the lowest numbered code will be displayed first.
        Fig 14: Identifying Blinking Pattern
        G04965397Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. After performing the check, disconnect the SST from terminals TS and CG, TC and CG of the DLC3 and turn the ignition switch off.
    4. Turn the ignition switch to the ON position.
  11. DTC OF SIGNAL CHECK FUNCTION (SST CHECK WIRE) (Procedure "J") 

    ABS sensor: 

    TROUBLE AREA CHART

    Code Code Detection Item Trouble Area
    C1271/71 Low Output Signal of Front Speed Sensor RH
    • Front speed sensor RH
    • Sensor installation
    • Speed sensor rotor
    C1272/72 Low Output Signal of Front Speed Sensor LH
    • Front speed sensor LH
    • Sensor installation
    • Speed sensor rotor
    C1273/73 Low Output Signal of Rear Speed Sensor RH
    • Rear speed sensor RH
    • Sensor installation
    • Speed sensor rotor
    C1274/74 Low Output Signal of Rear Speed Sensor LH
    • Rear speed sensor LH
    • Sensor installation
    • Speed sensor rotor
    C1275/75 Abnormal Change in Output Signal of Front Speed Sensor RH Speed sensor rotor
    C1276/76 Abnormal Change in Output Signal of Front Speed Sensor LH Speed sensor rotor
    C1277/77 Abnormal Change in Output Signal of Rear Speed Sensor RH Speed sensor rotor
    C1278/78 Abnormal Change in Output Signal of Rear Speed Sensor LH Speed sensor rotor
    C1279/79 Acceleration Sensor Output Voltage Malfunction
    • Yaw rate and acceleration sensor
    • Sensor installation
    C1281/81 Master Cylinder Pressure Sensor Output Malfunction
    • Stop light switch
    • Brake pedal load sensing switch
    • Master cylinder pressure sensor
    C1282/82 Center Differential Lock Position Switch Malfunction Center diff lock switch
    C1283/83 L4 Position Switch Malfunction Transfer indicator (L4) switch

    VSC sensor: 

    TROUBLE AREA CHART

    Code Code Detection Item Trouble Area
    C0371/71 Yaw Rate Sensor Yaw rate and acceleration sensor
    C1379/74 Malfunction in Downhill Assist Control Operation Switch Downhill assist control switch

    HINT:

    The codes in this table are output only in test mode (signal check).

  12. TEST MODE (SIGNAL CHECK) PROCEDURE (TECHSTREAM) 

    When having replaced the master cylinder solenoid and/or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor (See CALIBRATION  ).

    HINT:

    • If the ignition switch is turned from the ON to the ACC or LOCK position 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 codes left over are the codes where an abnormality was found.
    1. Turn the ignition switch off.
    2. Check that the steering wheel is in the straight-ahead position and move the shift lever to the P position.
    3. Connect Techstream to the DLC3.
    4. Turn the ignition switch to the ON position.
    5. Operate Techstream in test mode (Signal Check)

      HINT:

      Refer to Techstream operator's manual for further details.

    6. Check that the ABS and VSC TRAC warning lights blink in test mode.

      HINT:

      If the ABS and VSC TRAC warning lights do not blink, inspect the TS and CG terminal circuit and the ABS and VSC TRAC warning light circuits.

      TROUBLE AREA CHART

      Trouble Area See procedure
      TS and CG terminal circuit TS AND CG TERMINAL CIRCUIT 
      ABS warning light ABS WARNING LIGHT REMAINS ON  or ABS WARNING LIGHT DOES NOT COME ON 
      VSC TRAC warning light VSC TRAC WARNING LIGHT REMAINS ON  or VSC TRAC WARNING LIGHT DOES NOT COME ON 
      Fig 15: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    7. Start the engine.
    8. Using Techstream, perform the ABS sensor (acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch, L4 detection switch and speed sensor) and VSC sensor (yaw rate sensor and downhill assist control operation switch) signal checks in test mode (ABS sensor: See procedure "K" to "P", VSC sensor: See procedure "Q" to "S").
  13. ACCELERATION SENSOR SIGNAL CHECK (TECHSTREAM) (Procedure "K") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Keep the vehicle in a stationary condition on a level surface for 1 second or more.
      Fig 16: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  14. MASTER CYLINDER PRESSURE SENSOR SIGNAL CHECK (TECHSTREAM) (Procedure "L") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more for 1 second or more.
      Fig 17: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • At this time, the ABS warning light stays on for 3 seconds.
      • 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 the brake pedal operation above is performed.
  15. CENTER DIFF. LOCK DETECTION SWITCH SIGNAL CHECK (TECHSTREAM) (Procedure "M") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the center diff. lock switch.
      1. Push the center diff. lock switch on to lock the center differential.
      2. Push the center diff. lock switch off to unlock the center differential.
        Fig 18: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  16. L4 DETECTION SWITCH SIGNAL CHECK (TECHSTREAM) (Procedure "N") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the transfer indicator (L4) switch.
      1. Turn the H-L switch to the L position to put the vehicle in L4 mode.
      2. Turn the H-L switch to the H position to put the vehicle in H4 mode.
        Fig 19: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  17. SPEED SENSOR SIGNAL CHECK (TECHSTREAM) (Procedure "O") 
    1. Check that the ABS warning light is blinking in test mode.
    2. Check the backward signal.
      1. Drive the vehicle in reverse for more than 1 second at 3 km/h (2 mph) or higher.

        HINT:

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

        Fig 20: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the forward signal.
      1. Drive the vehicle straight forward. 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 or the steering wheel turned during this check.

    4. Stop the vehicle.
      NOTE:
      • Before performing the speed sensor signal check, complete the acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch and L4 detection switch signal 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, if the vehicle speed exceeds 80 km/h (50 mph), a signal check code will be stored again. Decelerate or stop 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 stationary.

  18. READ DTC OF ABS SENSOR (TECHSTREAM) (Procedure "P") 
    1. Read the DTC(s) by following the tester screen.

      HINT:

      • Refer to Techstream operator's manual for further details.
      • See the list of DTC (See procedure "T").
  19. YAW RATE SENSOR SIGNAL CHECK (TECHSTREAM) (Procedure "Q") 
    1. Check that the VSC TRAC warning light is blinking in test mode.
    2. Check the zero point voltage of the yaw rate sensor.
      1. Keep the vehicle in a stationary condition on a level surface for 1 second or more.
        Fig 21: Identifying Blinking Pattern
        G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the output of the yaw rate sensor and the direction of the steering angle sensor.
      1. Shift the shift lever to the D position and drive the vehicle at a vehicle 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 180° turn.
      2. Stop the vehicle and shift the shift lever to the P position. Check that the skid control buzzer sounds for 3 seconds.
        Fig 22: Identifying Start And End Position
        G04949577Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        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 (See SKID CONTROL BUZZER CIRCUIT  ), then perform the signal check again.
        • If the skid control buzzer still will not sound, there is a malfunction in the yaw rate sensor, so check the DTC.
        • Drive the vehicle in a 180° circle. At the end of the turn, the direction of the vehicle should be within 175° to 185° of its start position.
        • Do not spin the wheels.
  20. DOWNHILL ASSIST CONTROL OPERATION SWITCH SIGNAL CHECK (TECHSTREAM) (Procedure "R") 
    1. Check that the VSC TRAC warning light is blinking in test mode.
    2. Check the downhill assist control switch.
      1. Push the downhill assist control switch on.
      2. Push the downhill assist control switch off.
  21. READ DTC OF VSC SENSOR (TECHSTREAM) (Procedure "S") 
    1. Read the DTC(s) by following the tester screen.
      Fig 23: Identifying Blinking Pattern
      G05262648Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • Refer to Techstream operator's manual for further details.
      • See the list of DTC (See procedure "T").
  22. DTC OF SIGNAL CHECK FUNCTION (TECHSTREAM) (Procedure "T") 

    ABS sensor: 

    TROUBLE AREA CHART

    Code Code Detection Item Trouble Area
    C1271/71 Low Output Signal of Front Speed Sensor RH
    • Front speed sensor RH
    • Sensor installation
    • Speed sensor rotor
    C1272/72 Low Output Signal of Front Speed Sensor LH
    • Front speed sensor LH
    • Sensor installation
    • Speed sensor rotor
    C1273/73 Low Output Signal of Rear Speed Sensor RH
    • Rear speed sensor RH
    • Sensor installation
    • Speed sensor rotor
    C1274/74 Low Output Signal of Rear Speed Sensor LH
    • Rear speed sensor LH
    • Sensor installation
    • Speed sensor rotor
    C1275/75 Abnormal Change in Output Signal of Front Speed Sensor RH Speed sensor rotor
    C1276/76 Abnormal Change in Output Signal of Front Speed Sensor LH Speed sensor rotor
    C1277/77 Abnormal Change in Output Signal of Rear Speed Sensor RH Speed sensor rotor
    C1278/78 Abnormal Change in Output Signal of Rear Speed Sensor LH Speed sensor rotor
    C1279/79 Acceleration Sensor Output Voltage Malfunction
    • Yaw rate and acceleration sensor
    • Sensor installation
    C1281/81 Master Cylinder Pressure Sensor Output Malfunction
    • Stop light switch
    • Brake pedal load sensing switch
    • Master cylinder pressure sensor
    C1282/82 Center Differential Lock Position Switch Malfunction Center diff lock switch
    C1283/83 L4 Position Switch Malfunction Transfer indicator (L4) switch

    VSC sensor: 

    TROUBLE AREA CHART

    Code Code Detection Item Trouble Area
    C0371/71 Yaw Rate Sensor Yaw rate and acceleration sensor
    C1379/74 Malfunction in Downhill Assist Control Operation Switch Downhill assist control switch

    HINT:

    The codes in this table are output only in test mode (signal check).