Brake Control System

U1002 SYSTEM COMM (CAN)

Description

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.


DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


1. PRECONDITIONING

If "DTC CONFIRMATION PROCEDURE" has been previously conducted, always turn the ignition switch OFF
and wait at least 10 seconds before conducting the next test.
- GO TO 2.

2. DTC REPRODUCTION PROCEDURE

1.Turn the ignition switch OFF to ON.
2.Perform self-diagnosis for "ABS" with CONSULT.
Is DTC "U1002" detected?
YES- Proceed to diagnosis procedure. Refer to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


CAUTION:
- Never apply 7.0 V or more to the measurement terminal.
- Use a tester with open terminal voltage of 7.0 V or less.
- Turn the ignition switch OFF and disconnect the battery cable from the negative terminal when checking the harness.

1. CHECK CAN DIAGNOSIS SUPPORT MONITOR

1.Select "ABS" and "CAN Diagnosis Support Monitor" in order with CONSULT.
2.Check the malfunction history between each control unit connected to ABS actuator and electric unit (control unit).
Check the result of "PAST"?
All items are "OK"-Check the intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
"TRANSMIT DIAG" is other than "OK"-GO TO 2.
A control unit other than ABS actuator and electric unit (control unit) is anything other than "OK"-GO TO 3.

2. CHECK TRANSMITTING SIDE UNIT

Check the ABS actuator and electric unit (control unit) harness connector terminals No. 14 and 35 for damage or loose connection.
Is the inspection result normal?
YES- Erase self-diagnosis results. Then perform self-diagnosis for "ABS" with CONSULT.
NO- Recheck the terminals for damage or loose connection. Refer to "Precautions for Harness Repair" CAN Fundamental.

3. CHECK APPLICABLE CONTROL UNIT

Check the terminals of each harness connector for damage or loose connection.
Is the inspection result normal?
YES- Erase self-diagnosis results. Then perform self-diagnosis for applicable control unit with CONSULT.
NO- Recheck the terminals for damage or loose connection. Refer to "Precautions for Harness Repair" CAN Fundamental.


Special Repair Requirement


1. ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL POSITION

Always perform the neutral position adjustment for the steering angle sensor, when replacing the ABS actuator and electric unit (control unit) or steering angle sensor and removing steering angle sensor. Refer to BRC9, "ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL POSITION : Special Repair Requirement".
- END