Inspection Procedure 13: HSA does not work.

caution

If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the G and yaw rate sensor and the steering wheel sensor (Refer to and ).

COMMENTS ON TROUBLE SYMPTOM

The slope gradient may be low.
The vehicle is not completely stationary.
A failure may have occurred in the calibration of the G and yaw rate sensor.
The parking brake switch may be seized, which causes the HSA to fail to start the operation.
A problem (noise interference) may have occurred in the CAN bus line, resulting in an improper communication with ASC-ECU or each ECU.

note

The HSA does not work even when the wheel speed sensor output pulse (vehicle moved) while the vehicle is parked.
The HSA is affected by the loading conditions and vehicle posture at the occurrence of phenomenon. When checking the HSA operation in actual driving, carry out the check on the vehicle with one occupant (driver) only.

PROBABLE CAUSES

Calibration failure of the G and yaw rate sensor
Seizure of the parking brake switch
Malfunction of wheel speed sensor
Malfunction of CVT-ECU
Malfunction of hydraulic unit (integrated with ASC-ECU)
Wiring harness or connector failure of CAN bus line
Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. HSA function check.

Check if the HSA works with one occupant (driver) only in the vehicle.

Q. Is the check result normal?

	This diagnosis is complete.

	Go to Step 2.

STEP 2. Check the parking brake.

Check whether the parking brake warning lamp remains on with the parking brake lever not pulled up.

Q. Does the parking brake warning lamp remain on?

	Proceed to the symptom procedure "The parking brake warning lamp remains on with the parking brake lever not pulled up" (Refer to ). Then go to Step 10.

	Go to Step 3.

STEP 3. M.U.T.-III CAN bus diagnosis.

Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

	Go to Step 4.

	Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ). Then go to Step 10.

STEP 4. M.U.T.-III diagnosis code.

Use M.U.T.-III to check the diagnosis code for the ASC system.

Q. Is the diagnosis code set?

	Follow the relevant diagnosis code procedure (Refer to ). Then go to Step 10.

	Go to Step 5.

STEP 5. M.U.T.-III data list.

Evaluate the data list below.

Pull the parking brake lever.

Item No.	Item name	Normal conditions
30	Parking brake switch	Engage

Release the parking brake lever.

Item No.	Item name	Normal conditions
30	Parking brake switch	from "Engage" to "Disengage"

Q. Is the check result normal?

	Go to Step 6.

	Proceed to the symptom procedure "The parking brake warning lamp remains on with the parking brake lever not pulled up" (Refer to ). Then go to Step 10.

STEP 6. M.U.T.-III data list.

Evaluate the data list below.

Move the selector lever to "R", "D", "N" and "P".

Item No.

Item name

Normal conditions

Target gear

Selector lever position: "R"

"D1" to "D8"

Selector lever position: "D"

Selector lever position: "P"

Selector lever position: "N"

Actual gear

Q. Is the check result normal?

	YES : Go to Step 8.

	Go to Step 7.

STEP 7. M.U.T.-III Diagnosis code of other systems.

Use M.U.T.-III to check if the diagnosis code is set in the CVT-ECU.

Q. Is the diagnosis code set?

	Diagnose the CVT system (Refer to GROUP 23A - Troubleshooting ). Then go to Step 10.

	Go to Step 8.

STEP 8. M.U.T.-III data list.

Evaluate the data list below with one person on the driver’s seat and the vehicle otherwise unloaded (unladen weight) on a smooth flat surface (Refer to

Item No. 05: Longitudinal G sensor
Item No. 06: Lateral G sensor

Q. Is the check result normal?

	Go to Step 9.

	Calibrate the G and yaw rate sensor (Refer to ). Then go to Step 10.

STEP 9. Retest the system.

Check if the HSA works with one person on the driver’s seat.

Q. Is the check result normal?

	This diagnosis is complete.

	Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 10.

STEP 10. Retest the system.

Check if the HSA works with one person on the driver’s seat.

Q. Is the check result normal?

	This diagnosis is complete.

	Return to Step 2.