Vehicle Stability Control (VSC) & Brake Assist (BA) System - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM
1. Check the indicator.
  When the ignition switch is turned ON, check that the VSC warning light, VSC OFF indicator light and SLIP indicator light goes ON for 3 seconds.
  
  Fig 1: Identifying VSC Warning Light, VSC OFF & SLIP Indicator Lights
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  HINT:
  - If the ECU stores DTC, VSC warning light and VSC OFF indicator light is ON.
  - If the indicator check result is not normal, proceed to troubleshooting for the VSC warning light circuit, VSC OFF indicator light circuit, and SLIP indicator light circuit, refer to:
    - VSC WARNING LIGHT CIRCUIT
    
    - VSC OFF INDICATOR LIGHT, VSC OFF SWITCH CIRCUIT
    
    - SLIP INDICATOR LIGHT CIRCUIT
    
    Fig 2: Identifying DLC1 Connector Terminals E1 & TC
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. In case of not using LEXUS hand-held tester:
  Check the DTC
  1. Using SST, connect terminals TC and E₁ of DLC1.
    SST 09843-18020
  2. Turn the ignition switch ON.
  3. Read the DTC from the VSC warning light on the combination meter.
    HINT:
    - If no code appears, inspect the diagnostic circuit or VSC warning light circuit (See TC TERMINAL CIRCUIT or VSC WARNING LIGHT CIRCUIT ).
    - As an example, the blinking patterns for normal code and code 31 and 32 are shown in Fig 3.
  4. Codes, see DIAGNOSTIC TROUBLE CODE CHART .
  5. After completing the check, disconnect terminals TC and E1 of DLC1 and turn OFF the display.
    If 2 or more malfunctions are indicated at the same time, the lowest numbered DTC will be displayed 1st.
    
    Fig 3: Blinking Pattern For Normal Code And Code 31 And 32 (Example)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. In case of using LEXUS hand-held tester: Check the DTC.
  1. Hook up the LEXUS hand-held tester to the DLC3.
  2. Turn the ignition switch ON.
  3. Read the DTC by following the prompts on the tester screen.
    HINT:
    
    Refer to the LEXUS hand-held tester operator's manual for further details.
    
    Fig 4: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. In case of not using LEXUS hand-held tester: Clear the DTC.
  1. Using SST, connect terminals TC and E₁ of DLC1.
    SST 09843-18020
  2. Turn the ignition switch ON.
  3. Clear the DTC stored in ECU by depressing the brake pedal 8 or more times within 5 seconds.
  4. Check that the warning light shows the normal code.
  5. Remove the SST from the terminals of DLC1.
    SST 09843-18020
    
    Fig 5: Clearing DTC Stored In ECU By Depressing Brake Pedal
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. In case of using LEXUS hand-held tester: Clear the DTC.
  1. Hook up the LEXUS hand-held tester to the DLC3.
  2. Turn the ignition switch ON.
  3. Operate the LEXUS hand-held tester to erase the codes.
    (See LEXUS hand-held tester operator's manual)
    
    Fig 6: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Reference:
  Using LEXUS break-out-box and LEXUS hand-held tester, measure the ECU terminal values.
  1. Turn the ignition switch OFF.
  2. Hook up the LEXUS break-out-box and LEXUS hand-held tester to the vehicle.
  3. Turn the ignition switch ON.
  4. Read the ECU input/output values by following the prompts on the tester screen.
    
    Fig 7: Measuring ECU Terminals Values Using Break-Out-Box
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    HINT:
    - LEXUS hand-held tester has a "Snapshot" function. This records the measured values and is effective in the diagnosis of intermittent problems.
    - Refer to the LEXUS hand-held tester operator's manual for further details.
    HINT:
    
    If the ignition switch is turned from ON to ACC or LOCK during test mode, DTC will be erased.
In case of not using LEXUS hand-held tester:
VSC SENSOR CHECK (TEST MODE)

NOTE: When having replaced the yaw rate sensor, deceleration sensor and/or ECU, perform zero point calibration of the yaw rate and deceleration sensors (See step 4).

HINT:

If the ignition switch is turned from ON to ACC or LOCK during test mode, DTC will be erased.

Fig 8: Identifying DLC1 Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Procedures for test mode:
  1. Turn the ignition switch OFF.
  2. Check that the shift lever position is at P position, turn the steering wheel to the neutral position.
  3. Using SST, connect terminals Ts and E₁ of DLC1.
    SST 09843-18020
  4. Start the engine.
    
    Fig 9: Blinking Pattern For VSC Warning Light
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Check that the VSC warning light blinks.
    HINT:
    
    If the VSC warning light does not blink, inspect the VSC warning light circuit and Ts terminal circuit (See TS TERMINAL CIRCUIT and VSC WARNING LIGHT CIRCUIT ).
2. Check the steering angle sensor.
  Turn the steering wheel either to left or right for 450° or more from the vehicle stationary condition, and turn back the steering wheel to the straight ahead position.
  
  Fig 10: Identifying Vehicle Direction At End Of Turn As Compared To Start Position
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check the yaw rate sensor.
  Shift the shift lever to the D position and drive the vehicle at the vehicle speed of approx. 5 km/h (3 mph), turn the steering wheel either to left or right for 90° or more, and maintain 180° circular drive for the vehicle.
  
  Stop the vehicle and shift the shift lever to the P position, check that the VSC buzzer sounds for 3 sec.
  
  If the VSC buzzer sounded, the sensor check is in normal completion.
  
  If the VSC buzzer does not sound, do the sensor check again.
  
  If the VSC buzzer still won't sound, there is malfunction in the VSC sensor, so check the DTC.
  
  HINT:
  - Drive the vehicle circularly by 180°. At the end of the turn, the direction of the vehicle should be within 180° +/- 5° of its start position.
  - Do not spin the wheels.
4. Read the DTC.
  1. Using SST, connect terminals TC and E₁ of DLC1.
    SST 09843-18020
  2. Read the number of blinks of the VSC warning light.
    HINT:
    - See the DIAGNOSTIC TROUBLE CODE CHART .
    - If every sensor is normal, a normal code is output. (A cycle of 0.25 sec. ON and 0.25 sec. OFF is repeated.)
    - If 2 or more malfunctions are indicated at the same time, the lowest numbered code will be displayed 1st.
      
      Fig 11: Malfunction Code 71, 72 Blinking Pattern (Example)
      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. After doing the check, disconnect the SST from terminals of DLC1 and turn ignition switch OFF.
    SST 09843-18020
    
    Fig 12: Connecting Hand Held Tester To DLC3 For Checking VSC Sensor Signal
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
In case of using LEXUS hand-held tester: CHECK VSC SENSOR SIGNAL
NOTE: When having replaced the yaw rate sensor, deceleration sensor and/or ECU, perform zero point calibration of the yaw rate and deceleration sensors (See step 4). Make sure that this operation should be done before starting the following.
1. Hook up the LEXUS hand-held tester to the DLC3.
2. Do steps (a)-(2) and from (a)-(4) to (c) under 2.
3. Read the DTC by following the prompts on the tester screen.
  HINT:
  
  Refer to the LEXUS hand-held tester operator's manual for further details.
  
  DTC of the VSC sensor check function:
  
  Fig 13: DTC Table Of VSC Sensor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
IF NECESSARY, PERFORM ZERO POINT CALIBRATION OF YAW RATE AND DECELERATION SENSORS
HINT:
- When having replaced the yaw rate sensor, deceleration sensor or/and the ECU, make sure to perform yaw rate and deceleration sensors zero point calibration.
- This operation is also required when the deceleration sensor or yaw rate sensor has been replaced since the calibrated zero point of both sensors will be erased.
NOTE:
- While obtaining the zero point, do not give any vibration to the vehicle by tilting, moving or shaking it and keep it in a stationary condition. (Do not start the engine.)
- Be sure to do this on a level surface (within an inclination of 1 %).
1. Clear the zero point of the yaw rate and deceleration sensors.
  1. Shift the shift lever to P range.
  2. Turn the ignition switch ON in a stationary condition.
    
    Fig 14: Identifying DLC1 Connector Terminals E1 & TS
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. With the ignition switch ON, using SST, repeat a cycle of short and open between terminals Ts and E₁ of DLC1 4 times or more within 8 sec. Check that the VSC warning light is lit indicating the recorded zero point is erased.
    SST 09843-18020
  4. Turn the ignition switch OFF.
2. Obtain zero point of the yaw rate sensor.
  1. Make the terminals Ts and E₁ of DLC1 disconnected.
  2. Turn the ignition switch ON.
    HINT:
    
    The vehicle should be in a stationary condition with the shift lever in P range.
  3. Check that the lighted VSC warning light goes off about 15 sec. after the ignition switch is turned ON.
    HINT:
    
    Even if the ignition is not turned OFF in step (a)-(4) and remains ON, the yaw rate sensor zero point calibration can be completed. In this case, the VSC warning light is lit about 15 sec. and starts blinking. (Normal code)
  4. After ensuring that the VSC warning light remains OFF for 2 sec, turn the ignition switch OFF.
    HINT:
    
    If the ignition switch is not turned OFF in step (a)-(4), ensure the blinking light for 2 sec. and turn the ignition switch OFF.
3. Perform deceleration sensor zero point calibration.
  NOTE: After step (b) (the yaw rate sensor zero point calibration), the VSC warning light goes off. At this time, if the vehicle is driven without performing step (c) (deceleration sensor zero point calibration), deceleration sensor zero point calibration malfunction will be detected and the VSC warning light will light up. Therefore, perform step ( c) right after step ( b).
  
  Fig 15: Identifying DLC1 Connector Terminal E1 & TS
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Using SST, connect the terminals Ts and E₁ of DLC1.
    SST 09843-18020
  2. Turn the ignition switch ON.
    HINT:
    
    Make the vehicle in a stationary condition with the shift lever in P range.
    
    Fig 16: Blinking Pattern Of VSC Warning Light
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. After turning the ignition switch ON, check that the VSC warning light is lit for about 4 sec. and then starts quick blinking at 0.13 sec. intervals.
  4. After ensuring the blinking of the VSC warning light for 2 sec, turn the ignition switch OFF.
  5. Remove the SST and make the terminals Ts and E1 of DLC1 disconnected.
    SST 09843-18020