Code No. C1802: FCM-ECU fail



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 ).

DIAGNOSIS CODE SET CONDITIONS


When the ASC-ECU receives the FCM-LS brake operation request from the FCM-ECU continuously for 500 ms at the vehicle speed of 35 km/h or more, the diagnosis code is set.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. 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 3.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines.


Check again if the diagnosis code is set.
(1)Erase the set diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"
(4)Drive the vehicle at 35 km/h or more.

Q. Is diagnosis code No. C1802 set?

Go to Step 3.
This diagnosis is complete.

STEP 3. Check for diagnosis codes.


Check if diagnosis code(s) other than No. C1802 is set.

Q. Is the diagnosis code set?

Follow the relevant diagnosis code procedure, and then go to Step 7.
Go to Step 4.

STEP 4. Use M.U.T.-III to confirm a diagnosis code of FCM-LS system.


Check that the FCM-ECU diagnosis code(s) other than No. C1798 is set.

Q. Is the FCM-ECU diagnosis code(s) set?

Diagnose the FCM-LS (Refer to GROUP 54A - Forward Collision Mitigation System (Low speed range) (FCM-LS), Troubleshooting, Diagnosis Code Chart ). Then go to Step 7.
Go to Step 5.

STEP 5. Use M.U.T.-III to check a data list of FCM-ECU.


Check the data list of FCM-ECU. (Refer to GROUP 54A - FCM-LS, Troubleshooting, Data List Reference Table

  • Item 23: Vehicle speed

Q. Is the check result normal?

Go to Step 6.
Replace the laser radar (FCM-ECU) (Refer to GROUP 54A - Forward Collision Mitigation System (Low speed range) (FCM-LS), Laser Radar ). Then go to Step 7.

STEP 6. Check whether the diagnosis code is set again.


Check again if the diagnosis code is set.
(1)Erase the set diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"
(4)Drive the vehicle at 35 km/h or more.

Q. Is diagnosis code No. C1802 set?

Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to ). Then go to Step 7.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction).

STEP 7. Check whether the diagnosis code is set again.


Check again if the diagnosis code is set.
(1)Erase the set diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"
(4)Drive the vehicle at 35 km/h or more.

Q. Is diagnosis code No. C1802 set?

Return to Step 3.
This diagnosis is complete.