Electronic Brake Control Module: Testing and Inspection
ABS/TCS HU/CM (WITH TCS) OR ABS HU/CM (WITHOUT TCS) SYSTEM INSPECTIONSystem Inspection
Preparation
1. Verify that the battery is fully charged. With the ignition switch on, verify that the ABS and BRAKE system warning lights goes out after 3 seconds.
Note:
^ If the lights stays on after 3 seconds, the ABS HU/CM detects a failure. Follow the troubleshooting procedures.
2. Turn the ignition switch off.
3. On level ground, jack up the vehicle and support it evenly on safety stands. Shift the transaxle to N position.
4. Release the parking brake.
5. Rotate the wheels by hand, and inspect for brake drag.
Using the SSTs
1. Perform the "Preparation".
2. Connect the WDS or equivalent to DLC-2.
3. Set up an active command mode inspection according to the combination of commands.
The chart above shows an example of a right wheel inspection.
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 click sound indicating the solenoid is operating comes from the ABS/ TCS HU/CM (with TCS) or ABS HU/CM (without TCS), confirm that the wheel does not rotate. When pressure is being reduced, and click sound indicating the solenoid is operating comes from the ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS), confirm that the wheel rotates, even though the brake pedal is being depressed.
Note:
^ When working with two people, one should press on the brake pedal, the other should attempt to rotate the wheel being inspected.
^ To protect the ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS), 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 HU/CM (with TCS) or ABS HU/CM (without TCS) brake lines are normal
- The ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) hydraulic system is not significantly abnormal.
- The ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) wiring is normal.
^ However, the following items cannot be checked.
- ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) input system harness and parts
- Extremely small leaks in the ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) internal hydraulic system
- Unusual intermittent occurrences in the above items 1 through 3
Without using the SSTs
1. Perform the Preparation
2. Use a jumper wire to short terminal TBS of the DLC to body GND.
Caution:
^ Connecting the wrong data link connector (DLC) terminals may possibly cause a malfunction. Carefully connect the specified terminals only.
3. Depress the brake pedal, and have an assistant verify that the right front wheel does not turn.
4. With the brake pedal still depressed, turn the ignition switch on and verify that the brake is released momentarily (approx. 0.5 seconds) and that the wheel turns when pressure-reduction operates.
5. Inspect the operation of the remaining wheels in order: right front, left front, right rear, left rear.
^ Replace the ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) if wheels do not rotate.
^ Inspect brake piping to ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) if operation of the remaining wheel order is not within specified.
Note:
^ If Steps 4 and 5 show correct operation, the following systems are okay:
- Brake piping to ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS)
- Braking system, including ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS)
- Electrical system in ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) (solenoid, ABS motor, etc.)
^ The following are not inspected with above steps:
- Input system and harness of ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS)
- Intermittent failure
- Fluid leakage from brake including the ABS/TCS HU/CM (with TCS) or ABS HU/CM (without TCS) and master cylinder
6. Turn the ignition switch off and remove the jumper wire.