Diagnosis System (VDC/TCS/ABS Control Unit)
DIAGNOSIS SYSTEM (VDC/TCS/ABS CONTROL UNIT)
CONSULT-III Function
DIAGNOSIS SYSTEM
Description
When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the CONSULT-III to the vehicle and reading various data output from the vehicle's brake ECU.
The brake ECU records DTCs when the computer detects a malfunction in the computer itself or in its circuits.
To check for DTCs, activate the various actuators, and check the Freeze Frame Data and Data List.
1. Check the auxiliary battery voltage.
If the voltage is below 11 V, recharge the auxiliary battery before proceeding to the next step.
2. Check the DLC3.
The ECU uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with
SAE J1962 and matches the ISO 15765-4 format.
If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.
Verify the conditions listed in the table below.
NOTE:
- Connect the cable of the CONSULT-III to the DLC3, turn the ignition switch ON and attempt to use the tester.
If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester.
- If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. CONSULT-III the Service Department listed in the tester operator's manual.
Diagnosis
1. If the brake ECU detects a malfunction, the ABS warning lamp, brake warning lamp, Electronically Controlled Brake warning lamp, VDC warning lamp, and SLIP indicator lamp will come ON.
The table below indicates which lamps will come ON when there is a malfunction in a particular function.
Warning Lamp and Indicator Lamp Check
1. Release the parking brake.
CAUTION:
When replacing the parking brake, move the shift lever to the P position for safety.
NOTE:
When the parking brake is applied or the level of the brake fluid is low, the brake warning lamp comes on.
2. When the ignition switch is turned ON, check that the ABS warning, brake warning, Electronically Controlled Brake warning, and SLIP indicator lamps come ON and remain in until the ignition switch is turned
ON (READY).
NOTE:
If the warning lamp and indicator lamp check result is not normal, proceed to troubleshooting for the ABS warning, brake warning, Electronically Controlled Brake warning, VDC warning, and SLIP indicator lamp circuits.
If the indicator remains ON, proceed to troubleshooting for the lamp circuit below.
Symptom Simulation
NOTE:
The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. Then the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be reproduced. No matter how experienced or skilled a technician may be, if he proceeds to troubleshoot without confirming the problem symptoms, he will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting.
1. Vibration method: When vibration seems to be the major cause.
NOTE:
Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is turned ON.)
a. Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs.
b. Slightly shake the connector vertically and horizontally.
NOTE:
Shaking the relays too strongly may result in open relays.
c. Slightly shake the wire harness vertically and horizontally. The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.
FREEZE FRAME DATA
Freeze Frame Data/ Information
1. Whenever an ABS DTC is detected, the brake ECU stored the current vehicle (sensor) state as Freeze
Frame Data.
2. The brake ECU stores the number of times (maximum: 31) the ignition switch has been turned from off to ON since the last time the ABS was activated.
3. For DTCs memorized in the brake ECU, information (INF) codes that are contained in the Freeze Frame
Data can be displayed on the CONSULT-III.
NOTE:
- However, if the vehicle is stopped or at a low speed [7 km/h (4.3 MPH) or less], or if a DTC is detected, the brake ECU will stop counting the number.
- Freeze Frame Data at the time the ABS operates:
The brake ECU stores and updates data whenever the ABS system operates.
When the ECU stores data at time a DTC is detected, the data stored during ABS operation is erased.
- Freeze Frame Data at the time a DTC is detected:
When the brake ECU stores data at the time a DTC is detected, no updates will be performed until the data is cleared.
Check Freeze Frame Data and Information
Clear Freeze Frame Data and Information
CAUTION:
Clearing the DTC will also clear the Freeze Frame Data and information (INF) cord.
1. Connect the CONSULT-III.
2. Turn the ignition switch ON.
3. Clear the DTC and Freeze Frame Data. SEE CONSULT-III Function.
FAIL-SAFE CHART
Fail-Safe Function
1. If a malfunction occurs in the brake ECU, sensor signal, or actuator, rest normally operating parts will maintain brake control.
2. When trouble occurs in the brake control system, the brake ECU turns the warning lamp ON, and prohibits
ABS, TCS and VDC operations.
NOTE: A malfunction in the ABS system will result in an identical operation, with ABS, TCS and VDC system control prohibited.
NOTE: As for the TCS and VDC systems, different systems prohibit different controls depending on a malfunctioning part.
3. The brake ECU prevents operation of a malfunctioning hydraulic pressure system and continues brake control with the normal hydraulic pressure system.
NOTE:
- If control of the Electronically Controlled Brake for any of the 4 wheels is prohibited, that wheel loses brake booster function or braking ability.
- If one of the 4 wheels loses brake booster function, the feeling when depressing the brake pedal changes.
- If control of the Electronically Controlled Brake for all wheels is prohibited, the 2 front wheels will lose brake booster function.
4. If the brake control is stopped under such conditions as when trouble occurs with a hydraulic pressure source, the pressure generated in the master cylinder by the driver is applied to the wheel cylinder to ensure braking force.
5. A power back-up until is built in as an additional power source to supply stable power to the system.
6. If the regenerative brake alone does not operate under such conditions as a communication error with the
HV ECU, control is switched so that all braking force is generated with the hydraulic pressure brake.
DATA MONITOR
NOTE:
With the CONSULT-III connected to the DLC and the ignition switch ON, the Electronically Controlled Brake, ABS, and VDC Data List can be displayed. Follow the prompts on the tester screen to access the Data List.
ACTIVE TEST
NOTE:
Performing the Active Test using the CONSULT-III allows the relay, actuator, and other items to operate without removing any parts. Performing the Active Test as the first step in troubleshooting is one of the methods to save labor time.
It is possible to display the Data List during the Active Test.
1. On the tester display, select the Active Test.
NOTE:
The ignition switch must be turned ON to proceed to the Active Test using the CONSULT-III.
WORK SUPPORT
NOTE:
- 1: Electronically Controlled Brake warning lamp turns ON during TEST MODE.
- 2:Where TEST MODE is prolonged, be sure to exit from TEST MODE after the completion of a work.
ERASE MEMORY
How to Erase Self-diagnosis Result
After erasing DTC memory, start engine and drive vehicle at 30 km/h (19 MPH) or more for approximately 1 minute as the final inspection, and make sure that the VDC warning lamp, SLIP indicator lamp and Electronically Controlled Brake warning lamp turn OFF.
CAUTION:
If memory cannot be erased, perform applicably diagnosis.
Erase Memory
1. Select "MEMORY ERASING" in "WORK SUPPORT" to erase memory of brake ECU.
CAUTION:
- Do not touch steering wheel while erasing memory.
- When a memory is erased, stored value of zero point for each sensor and leaning value of linear solenoid valve offset are also erased. Therefore, remember to perform zero adjustment for each sensor and initialization of linear solenoid valve.
- Steering angle sensor: Description.
- Yaw rate/side/decel G sensor: .
- Stroke sensor: Description.
- Linear solenoid valve: .
- VDC warning lamp turns ON when stored zero point of steering angle sensor is erased. VDC warning lamp turns OFF after performing zero adjustment for steering angle sensor. If VDC warning lamp does not turn OFF, perform self-diagnosis for brake ECU.