Antilock Brakes / Traction Control Systems: Service Precautions
BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: PRECAUTION
PRECAUTION
1. PRECAUTION FOR DISCONNECTING THE BATTERY CABLE
NOTE: When disconnecting the battery negative (-) cable, initialize the following systems after the cable is reconnected:
2. TROUBLESHOOTING PRECAUTIONS
(a) When there is a malfunction with terminal contact points or part installation problems, removal and installation of the suspected problem parts may return the system to the normal condition either completely or temporarily.
(b) In order to determine the malfunctioning area, be sure to check the conditions at the time the malfunction occurred, such as DTC output and the Freeze Frame Data, and record it before disconnecting each connector or removing and installing parts.
(c) Since the system may be influenced by malfunctions in systems other than the brake control system, be sure to check for DTCs in other systems.
3. HANDLING PRECAUTIONS
(a) Do not remove or install electronically controlled brake system parts such as the steering angle sensor, yaw rate and acceleration sensor or brake pedal stroke sensor except when required, as they cannot be adjusted correctly after removal or installation.
(b) 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 electronically controlled brake system.
(c) Be sure that the power switch is off when removing and installing the ECU, actuator, each sensor, etc. unless it is specified otherwise in the inspection procedure.
(d) Be sure to remove the 2 ABS main relays before removal, installation, or replacement of electronically controlled brake system parts.
(e) The removal or installation of the actuator, master cylinder or stroke simulator as well as other procedures can cause the brake fluid level to drop below the fluid reservoir. If this happens when performing such work, be sure to remove the 2 motor relays until the brake line has been bled.
HINT:
- If the pump motor is operated while there is air in the brake actuator hose, bleeding the air becomes difficult due to air in the actuator.
- The skid control ECU may operate the stroke simulator and drive the pump motor even when the power switch is off.
- With the power switch off, the skid control ECU can be operated for 2 minutes after operating the brake pedal.
(f) Removal of the ABS main relay and ABS motor relay.
(1) Wait for 2 minutes after turning the power switch off, operating the brake pedal and closing the driver door before removing the 2 relays.
HINT: The skid control ECU operates the pump motor just before the brake control system shuts down in order to prepare the system for the next time it is operated.
(g) 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 Techstream, also check that system functions and signals received by the ECU are normal using Test Mode.
4. DTC PRECAUTION
(a) Warnings for some DTCs cannot be cleared only by repairing the malfunctioning parts. If the warning is displayed even after repair work, the DTC should be cleared after turning the power switch off.
NOTE: If a DTC for a malfunctioning part reappears after it was cleared, then it has been stored again.
5. CHASSIS DYNAMOMETER PRECAUTION
(a) Enter Test Mode to disable TRAC and VSC control when using a chassis dynamometer. Service Precautions
HINT: The vehicle may unexpectedly slip off the dynamometer because of TRAC and VSC operation.
NOTICE:
- Make sure that the brake warning / yellow (minor malfunction) and master caution indicator (VSC warning) lights blink (Test Mode is activated).
- Secure the vehicle with a lock chain for safety.
6. CAN COMMUNICATION SYSTEM PRECAUTIONS
(a) The CAN communication system is used for the data communication between the skid control ECU, the steering angle sensor, yaw rate and acceleration sensor and other ECUs. If there are any problems in the CAN communication line, corresponding DTCs in the communication line are stored.
(b) If any CAN communication line DTCs are output, repair the malfunction in the communication line and troubleshoot the electronically controlled brake system when data communication is normal.
(c) 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 that have an equal length. A bypass wire should not be used, because the data being transmitted will be corrupted.