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Inspection Procedure 13: HSA (Hill Start Assist) does not work.
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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.
 
 
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 or brake fluid pressure 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
  • Calibration failure of the brake fluid pressure sensor
  • Malfunction of wheel speed sensor (external noise interference)
  • Malfunction of combination meter (parking brake signal related)
  • Malfunction of transmission (shift position signal related)
  • Malfunction of hydraulic unit (integrated with ASC-ECU)
 
 
 
 
DIAGNOSIS
STEP 1. Parking brake check.
With the parking brake not pulled, check if the brake warning light is off.
Is the check result normal?
Go to Step 2.
Carry out Inspection procedure 3 "The brake warning light does not go out (ABS warning light is OFF) although the parking brake is released" (Refer to ).
 
STEP 2. Using scan tool (M.U.T.-IIISE) data list.
Check the following data list (Refer to ).
  • Item No.14: Actual gear
  • Item No.15: Target gear
Is the check result normal?
Go to Step 3.
Use M.U.T.-IIISE to check that the diagnostic trouble code is set in the TCM (Refer to GROUP 23A - Troubleshooting, Diagnostic trouble code chart ).
 
STEP 3. Using scan tool (M.U.T.-IIISE) data list.
Check the following data list under curb weight condition or one occupant (driver) only in the vehicle, on a flat road (Refer to ).
  • Item No.06: Yaw rate sensor
  • Item No.09: G sensor
Is the check result normal?
Go to Step 4.
Carry out the calibration of the G and yaw rate sensor (Refer to ) and then go to Step 7.
 
STEP 4. Using scan tool (M.U.T.-IIISE) data list.
Check the following data list (Refer to ).
  • Item No.07: Master cylinder pressure sensor
Is the check result normal?
Go to Step 5.
Carry out the calibration of the brake fluid pressure sensor (Refer to ) and then go to Step 7.
 
STEP 5. Wheel speed sensor installation check.
Check whether a device or a wiring harness other than Mitsubishi genuine parts is installed near the wheel speed sensor. (Refer to <Front>, <Rear>).
Is the check result normal?
Go to Step 6.
Remove the device and the wiring harness other than Mitsubishi genuine parts.
 
STEP 6. Using scan tool (M.U.T.-IIISE) data list
Check the following data list (Refer to ).
  • 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
Is the check result normal?
Go to Step 7.
Check the installation status of corresponding wheel speed sensor (Refer to <Front> or <Rear>).
 
STEP 7. Retest the system.
Check if the HSA works with one occupant (driver) only in the vehicle.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).