Antilock Brakes / Traction Control Systems: Service Precautions
BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: PRECAUTION
PRECAUTION
NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected.
1. TROUBLESHOOTING PRECAUTIONS
(a) When there is a malfunction with terminal contact points or problem with part installation, 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 this system may be influenced by malfunctions in systems other than the brake control system, be sure to also check for DTCs in other systems.
2. HANDLING PRECAUTIONS
(a) Do not remove or install the electronically controlled brake system parts such as the steering sensor, yaw rate sensor or brake pedal stroke sensor except when required, as they need to be adjusted correctly after removal or installation.
(b) Be sure to complete preparation before work and confirmation after work by following the direction in the repair procedure when working on the electronically controlled brake system.
(c) Be sure to remove and install the ECU, actuator, each sensor, etc. with the power switch OFF unless it is not specified in the inspection procedure.
(d) Be sure to remove the 2 main relays before removal and installation, or replacement of the electronically controlled brake system parts.
(e) The removal or installation of the actuator, master cylinder or stroke simulator as well as some other procedures can cause the fluid level to drop below the fluid reservoir port. If this happens when performing such work, be sure to remove the 2 motor relays before the bleeding of the air in the pipeline is completed.
HINT:
- When the pump motor is operated with the air in the brake actuator hose, bleeding of the air becomes difficult due to the air in the actuator.
- The skid control ECU may operate the stroke simulator and drive the pump motor even when the power switch is turned OFF.
- Even with the power switch turned OFF, the skid control ECU can be operated for 2 minutes after the brake operation is finished.
(f) Removal of the main relay and motor relay.
(1) With the power switch OFF and the driver door closed, wait for 2 minutes without depressing the brake pedal. Make sure the brake control system is off. Then remove the 2 relays.
HINT: Just before the brake control system turns off, the pump motor will operate for several seconds to prepare for its next operation.
(g) When removing and installing the ECU, actuator and each sensor, be sure to check that the normal display is output in the Test Mode inspection and in DTC output inspection after installing all the parts.
3. DTC PRECAUTION
(a) Warnings for some DTCs cannot be cleared only by repairing the malfunctioning parts. If the warning is displayed after repair work, the DTC should be cleared after turning the power switch OFF.
NOTE: If a part is still malfunctioning even after the DTC is cleared, the DTC will be stored again.
4. CHASSIS DYNAMOMETER PRECAUTION
(a) Disable TR(A)C and VSC control when using a chassis dynamometer.
When testing with 2-wheel drum tester such as a speedometer tester, a combination tester for the speedometer and brake, a chassis dynamometer, or when jacking up the rear wheels and turning the wheels, enter the Maintenance Mode with the Techstream and turn traction control off and the VSC system off.
CAUTION: If the vehicle is tested in normal mode on the drum tester, the traction control and VSC system may cause the vehicle to jump out from the drum tester.
NOTICE:
- Check that the slip indicator light illuminates on the combination meter.
- For safety, secure the vehicle with restraint chains while using a drum tester.
5. CAN COMMUNICATION SYSTEM PRECAUTION
(a) The CAN communication system is used for the data communication between the skid control ECU, the steering sensor, the yaw rate sensor (acceleration sensor included) and other ECUs. If there is trouble with the CAN communication line, corresponding DTCs in the communication line will be output.
(b) If the DTC in the CAN communication line is output, repair the malfunction in the communication line and troubleshoot the electronically controlled brake system while data communication is normal.
(c) Since the CAN communication line has a specific length and route, it cannot be repaired temporarily with a bypass wire, etc.