Inspection Procedure 9

Inspection Procedure 9: ABS operate too frequently.

COMMENTS ON TROUBLE SYMPTOM

- Although the cause of the trouble cannot be clearly resolved since it depends on the running status and road surface condition, the malfunction of the hydraulic circuit may occur if any diagnostic trouble code is not detected.

- If wheels and tires other than the ones with genuine specified size are mounted, the ABS may be activated prematurely.

- If a non-genuine braking device or non-genuine impact reduction device is mounted, the ABS may be activated prematurely.

PROBABLE CAUSES

- Mounting of wheels and tires other than with genuine specified size

- Tire pressure abnormality

- Tire wear and deterioration

- Mounting of non-genuine braking device or impact reduction device

- Wheel alignment abnormality

- Malfunction of brake related parts

- ABS-ECU malfunction

- Malfunction of hydraulic circuit

- External radio wave noise interference

DIAGNOSIS PROCEDURE

STEP 1. Check the wheels and the tires.

Carry out the following check.

- Size check of wheels and tires

- Tire wear and deterioration statuses

- Check the tire pressure.
NOTE:
For the tire pressure, refer to the tire pressure label attached to the lower section of driver's side door striker.

Q. Is the check result normal?

YES Go to Step 2.
NO Correct the wheels and tires in good condition. Then go to Step 9.
STEP 2. DTC check

Use scan tool to check the DTC for the ABS system (Refer to Anti-Lock Braking System (ABS)).

Q. Is the check result normal?

YES Go to Step 3.
NO Carry out the diagnosis for the DTC (Refer to Anti-Lock Braking System (ABS)).
Then go to Step 9.
STEP 3. Check of brake system related components other than hydraulic unit (integrated with ABS-ECU)

At the same time with the following checks, also check that no parts other than the genuine parts are mounted.

- Brake pad check Brake Pad Check).

- Brake disk runout check Brake Disc Check).

- Brake drag force check Removal and Installation [Front] or Rear Disc Brake Assembly Rear Disc Brake Assembly Removal and Installation [Except Ralliart] [Rear]).

Q. Is the check result normal?

YES Go to Step 4.
NO Repair or replace the part(s) having damage or other problems. Then go to Step 9.
STEP 4. Wheel alignment check

At the same time with the following checks, also check that no parts other than the genuine parts are mounted.

- Front wheel alignment check Front Suspension).

- Rear wheel alignment check Rear Suspension).

Q. Is the check result normal?

YES Go to Step 5.
NO Repair or replace the part(s) having damage or other problems. Then go to Step 9.
STEP 5. M.U.T.-III data list

Check the following data list (Refer to Data List Reference Table).

- Item No.01: FL wheel speed sensor

- Item No.02: FR wheel speed sensor

- Item No.03: RL wheel speed sensor

- Item No.04: RR wheel speed sensor

Q. Is the check result normal?

YES Go to Step 7.
NO Go to Step 6.
STEP 6. Wheel speed sensor check

Check that no non-genuine electronic device or no wiring harness of other than genuine electronic device is mounted near the wheel speed sensor (at wheel speed detection section and wiring harness section) (Refer to Anti-Lock Braking System (ABS)).

Q. Is the check result normal?

YES Go to Step 7.
NO Remove the non-genuine electronic device or the wiring harness of non-genuine electronic device. Then go to Step 9.
STEP 7. Hydraulic unit check

Carry out the following actuator tests, and check if they work normally (Refer to Actuator Test Reference Table).

- Item No.01: FL wheel ABS

- Item No.02: FR wheel ABS

- Item No.03: RL wheel ABS

- Item No.04: RR wheel ABS

Q. Is the check result normal?

YES Go to Step 8.
NO Replace the hydraulic unit (integrated with ABS-ECU) (Refer to Anti-Lock Braking System (ABS)).
Then go to Step 9.
STEP 8. ABS operation check

Q. Is the check result normal?

YES Intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the hydraulic unit (integrated with ABS-ECU) (Refer to Anti-Lock Braking System (ABS)).
Then go to Step 9.
STEP 9. ABS operation check

Q. Is the check result normal?

YES The procedure is complete.
NO Return to Step 1.