Diagnosis System

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM (for ADVICS Made): DIAGNOSIS SYSTEM

1. DESCRIPTION

When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the Techstream to the vehicle and reading various data output from the vehicle's skid control ECU.

The skid control ECU records DTCs when the computer detects a malfunction in the ECU itself or in its circuits.

To check for DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream enables you to clear the DTCs, activate the various actuators, and check the Freeze Frame Data and Data List.

(a) Check the battery voltage.

Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge the battery before proceeding.

(b) 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.





NOTICE:
*: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors.

HINT
Connect the Techstream to the DLC3, turn the ignition switch on (IG) and attempt to use the Techstream. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the Techstream.

* If communication is normal when the Techstream is connected to another vehicle, inspect the DLC3 on the original vehicle.
* If communication is still not possible when the Techstream is connected to another vehicle, the problem may be in the Techstream itself. Consult the Service Department listed in the Techstream operator's manual.

2. DIAGNOSIS

(a) If the skid control ECU detects a malfunction, the ABS warning, BRAKE warning, SLIP indicator and master warning lights will come on in order to warn the driver.

(b) The DTCs are simultaneously stored in the memory. The DTCs can be read by connecting SST between terminals TC and CG of the DLC3 and observing the blinking pattern of the ABS warning and SLIP indicator lights, by reading the multi-information display (models with multi-information display), or by connecting the Techstream.

(c) This system has Test Mode (signal check) function Test Mode Procedure.

The DTC can be read by connecting the Techstream and observing the blinking pattern of the ABS warning and SLIP indicator lights or by reading the multi-information display (models with multi-information display).

3. WARNING LIGHT AND INDICATOR LIGHT CHECK

(a) Release parking brake.

NOTICE:
When releasing parking brake, move the shift lever to P for safety.

HINT
When parking brake is applied or the level of the brake fluid is low, the BRAKE warning light comes on.

(b) When ignition switch is turned on (IG), check that the ABS warning, BRAKE warning, TRAC OFF indicator, VSC OFF indicator and SLIP indicator lights come on for approximately 3 seconds.

HINT
* If the warning light and indicator light initial check result is not normal, proceed to troubleshooting for the ABS warning, BRAKE warning, TRAC OFF indicator, VSC OFF indicator and SLIP indicator light circuits.
* If the indicator remains on or does not come on, proceed to troubleshooting for the light circuits listed below.





4. SYMPTOM SIMULATION

HINT
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 they proceeds to troubleshoot without confirming the problem symptoms, they will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting.

(a) Vibration method: When vibration seems to be the major cause.





HINT
Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is on (IG)).

(1) Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs.

(2) Slightly shake the connector vertically and horizontally.

HINT
Shaking the relays too strongly may result in open relays.

(3) Slightly shake the wire harness vertically and horizontally. The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.