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.
OPERATION
ASC-related signals are sent or received between the electric parking brake ECU and the ASC-ECU via CAN bus lines.
DTC SET CONDITIONS
The DTC will be set under any of the following conditions:
The system receives an invalid longitudinal G-sensor signal.
The system detects an implausible longitudinal G-sensor signal.
The system receives an invalid road wheel speed sensor signal.
The system detects an implausible road wheel speed sensor signal.
The system receives an invalid brake fluid pressure sensor signal.
The system detects an implausible brake fluid pressure sensor signal.
The system detects an implausible electric parking brake request signal.
The system detects that the emergency brake function fails.
TROUBLESHOOTING HINTS
The ASC system fails
Power supply voltage
Longitudinal G-sensor
wheel speed sensor
Brake fluid pressure sensor
Emergency brake function
The CAN bus line is defective (noise interference).
Malfunction of the electric parking brake ECU
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose CAN bus line
(1)
caution
To prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to Connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the DTC is set.
Use scan tool (M.U.T.-IIISE) to check that any DTC other than DTC U0415 is set in electric parking brake ECU.
Is the DTC set?
Troubleshoot the relevant DTC (Refer to ).
Go to Step 3.
STEP 3. Using scan tool (M.U.T.-IIISE), check whether the other DTC is set.
Use scan tool (M.U.T.-IIISE) to check that any DTC other than DTC U0417 is set in ASC-ECU.
Is the DTC set?
Troubleshoot the ASC-ECU DTC (Refer to GROUP 35C - Diagnostic Trouble Code Chart ).
Go to Step 4.
STEP 4. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3) Turn the ignition switch to the ON position.
(4) Check the DTC.
Is the DTC U0415 set?
Go to Step 5.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
STEP 5. Using scan tool (M.U.T.-IIISE), check the data list.
Check the ASC-ECU data list (Refer to GROUP 35C - Data List Reference Table ).
Item No.
Item name
Normal condition
34
A.S.C. dynamic brake fail
Normal
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 6.
Replace the electric parking brake ECU (Refer to ).
STEP 6. Using scan tool (M.U.T.-IIISE), check the data list.
Check the ASC-ECU data list (Refer to GROUP 35C - Data List Reference Table ).
Item No.
Item name
Normal condition
31
EPB fail state
Normal
OK: Normal condition is displayed.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to GROUP 35C - Hydraulic Unit ).