Electronic Brake Control Module: Testing and Inspection
ABS/TCS MU/CM SYSTEM INSPECTIONSystem Inspection Preparation
1. Verify that the battery is fully charged. With the ignition switch at ON, verify that the ABS and BRAKE system warning lights go out after 3 seconds.
2. If the lights stay on after 3 seconds, the ABS/TCS MU/CM detects a failure. Follow the troubleshooting procedures.
3. Turn the ignition switch to OFF.
4. On level ground, jack up the vehicle and support it evenly on safety stands. Shift the transaxle to N position.
5. Release the parking brake.
6. Rotate the wheels by hand, and inspect for brake drag.
Operation of ABS inspection
1. Perform the "Preparation."
2. Connect WDS or equivalent to the DLC-2.
3. Set up an active command mode inspection / according to the combination of commands.
The chart shows an example of a right wheel inspection.
Note: When working with two people, one should press on the brake pedal, the other should attempt to rotate the wheel being inspected.
4. Send the command while pressing on the brake pedal and attempting to rotate the wheel being inspected.
5. When pressure is being maintained, and a click sound indicating the solenoid is operating comes from the ABS/TCS MU/CM, confirm that the wheel does not rotate. When pressure is being reduced, and a click sound indicating the solenoid is operating comes from the ABS/TCS MU/CM, confirm that the wheel rotates, even though the brake pedal is being depressed.
Note:
^ To protect the ABS/TCS MU/CM, the solenoid valve used for simulations and the ABS motor stay on for 10 seconds each time they are switched on.
^ Performing the inspections above determines the following.
- The ABS/TCS MU/CM brake lines are normal.
- The ABS/TCS MU/CM hydraulic system is not significantly abnormal.
- The ABS/TCS MU/CM wiring is normal.
^ However, the following items cannot be checked.
- ABS/TCS MU/CM input system harness and parts.
- Extremely small leaks in the ABS/TCS MU/CM internal hydraulic system
- Unusual intermittent occurrences in the above items.
ABS/TCS MU/CM INSPECTION
1. Disconnect the negative battery cable.
2. Connect the SST between the ABS/TCS MU/CM and harness connector with the ignition switch off.
3. Attach the tester leads to the SST and inspect voltage.
Terminal Voltage Table (Reference)
(Engine is idling, and connector is connected unless otherwise indicated)
Inspection Using An Oscilloscope (Reference) Wheel speed
^ ABS/TCS MU/CM terminal:
RR: A(+)-B(-)
LR: C(+)-F(-)
RF: G(+)-D(-)
LF: I(+)-E(-)
^ Oscilloscope setting: 1 V/DIV (Y), 2 ms/DIV (X), AC range
^ Vehicle condition: Driving 30 km/in (18.6 mph)
Note:
^ As vehicle speed increases, the wave period shortens.
^ If there is malfunctioning in the sensor rotor, the wave profile warps.
Vehicle speed output
^ ABS/TCS MU/CM terminal: V( + )-AC ( - )
^ Oscilloscope setting: 1 WDIV (Y), 5 ms/DIV (X), DC range
^ Vehicle condition: Driving 30 km/in (18.6 mph)
Note: As vehicle speed increases, the wave period shortens.