Code No. C1777: System Fail Detected (ASC)


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 - Troubleshooting ).
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
  • When the ACC/FCM-ECU is replaced, calibrate the radar (refer to ).

OPERATION


The ACC/FCM-ECU receives system fault information from the ASTC-ECU.

DIAGNOSIS CODE SET CONDITION


The ACC/FCM-ECU sets the diagnosis code when it receives system fault information from the ASTC-ECU.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Use M.U.T.-III to confirm a diagnosis code of other systems.
caution If you have started this procedure as a result of diagnosis procedure for diagnosis code No. C1804, which is set in the ASTC-ECU, go to Step 3. It is not necessary to troubleshoot the diagnosis code set in the ASTC-ECU.
Check if any diagnosis code other than below is set in the ASTC-ECU (Refer to GROUP 35C - Troubleshooting <ASTC-ECU>, Diagnosis Function).

  • Code No. C1804: ACC deactivation disagreement
  • Code No. U1014: FCM (CAN message)
  • Code No. U1101: A/T-ECU timeout error
  • Code No. U15A0: ACC/FCM-ECU CAN timeout

Q. Is any of the diagnosis code other than above set?
Troubleshoot the ASTC-ECU diagnosis code (Refer to GROUP 35C - Troubleshooting <ASTC-ECU>, Diagnosis Code Chart ).
Go to Step 3.

STEP 3. Use M.U.T.-III to confirm a diagnosis code of the systems.
Check if other diagnosis code is set in the ACC/FCM-ECU (Refer to ).

Q. Is other diagnosis code set?
Troubleshoot the ACC/FCM-ECU diagnosis code (Refer to ).
Go to Step 4.

STEP 4. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the ACC/FCM-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Start the engine.
(4)Press the ACC ON/OFF switch to turn the ACC system to ON.
(5)On completion, check that the diagnosis code is set again.

Q. Is diagnosis code No. C1777 set?
Replace the ACC/FCM-ECU (Refer to ).
Go to Step 5.

STEP 5. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the ACC/FCM-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Start the engine.
(4)Press the ACC ON/OFF switch to turn the ACC system to ON.
(5)On completion, check that the diagnosis code is set again.

Q. Is diagnosis code No. C1777 set?
Replace the hydraulic unit assembly (integrated with ASTC-ECU) {Refer to GROUP 35C - Hydraulic Unit Assembly}.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction).