Vehicle Stability Control System (For Vacuum Brake Booster) Precaution

When there are problems with terminal contact points or part installation problems, removal and installation of the suspected problem parts may completely or temporarily return the system to normal.

In order to determine the malfunctioning area, check the conditions at the time the malfunction occurred, such as stored DTC output and the freeze frame data, and record them before disconnecting each connector or removing and installing parts.

Since the VSC system may be influenced by malfunctions in other systems, be sure to check for DTCs in the other systems.

Do not remove or install VSC parts such as the steering angle sensor or the yaw rate and acceleration sensor except when required, as they cannot be adjusted correctly after removal or installation.

Be sure to perform preparation before work and confirmation after work is completed by following the directions in the repair manual when working on the VSC system.

Be sure to remove and install the ECU, brake actuator and each sensor, etc. with the ignition switch off unless otherwise specified in the inspection procedure.

If the ECU, brake actuator or a sensor has been removed and installed, it is necessary to check the system for problems after the parts have been reassembled. Check for DTCs using the intelligent tester, and also check that system functions and signals received by the ECU are normal using test mode.

Some DTCs cannot be cleared only by repairing the malfunctioning parts. If the DTC is output after repair work, turn the ignition switch off to clear the DTC.

NOTICE:

If a part is still malfunctioning even after the DTC is cleared, the DTC is stored again.

The CAN communication system is used for data communication between the skid control ECU, the steering angle sensor, the yaw rate and acceleration sensor and other ECUs. If there is trouble in the CAN communication line, corresponding communication line DTCs are stored.

If any CAN communication line DTC is output, repair the malfunction in the communication line and troubleshoot the VSC system after data communication becomes normal.

In order to enable CAN communication, a specific type of wiring is used for the CAN communication lines. The wiring used for each communication line is a twisted pair of wires of equal length. A bypass wire should not be used because the data being transmitted will be corrupted.

Disable the TRC and VSC controls when using a chassis dynamometer.

1. When testing with a drum tester, such as a speedometer tester, a combination tester for the speedometer and brake, or a chassis dynamometer, or when jacking up the front wheels and turning the wheels, perform the following procedure to enter inspection mode and stop the TRC and VSC systems.
   Enter inspection mode to disable TRC and VSC control when using a chassis dynamometer (LandCruiser RM000003YMD00TX.html).
   

2. When testing with a drum tester, such as a speedometer tester, a combination tester for the speedometer and brake, or a chassis dynamometer, enter test mode using the intelligent tester, or switch to VSC OFF mode to turn TRC and VSC operation off using the VSC OFF switch.
   

   CAUTION:

   Secure the vehicle with a lock chain for safety.

   HINT:

   1. The vehicle may move unexpectedly out of the dynamometer because of TRC and VSC operations.
      
   2. Pressing the VSC OFF switch does not disable TRC and VSC operations completely.
      

When CAN communication is impossible due to malfunctions of the CAN communication line, it is also impossible to check for DTCs using the intelligent tester.