Code No. C1802
FCM ECU fail <Vehicles with FCM-LS>
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- 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
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- 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 steering wheel sensor and the G and yaw rate sensor (Refer to and ).
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OPERATION
FCM-LS related signals are sent or received to and from between ASC-ECU and FCM-ECU via
CAN bus lines.
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
- The CAN bus line is defective (noise contamination)
- Malfunction of the laser radar (integrated with FCM-ECU)
- Malfunction of the hydraulic unit assembly (integrated with ASC-ECU).
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STEP 1. M.U.T.-III CAN bus diagnosis
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 3.
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 Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).
On completion, go to Step 2.
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STEP 2. Diagnosis code recheck after resetting CAN bus lines
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Check again if the diagnosis code is set.
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(1)Erase the set diagnosis code.
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(2)Ignition switch: "LOCK" (OFF)
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(4)Drive the vehicle at 35 km/h or more.
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Q.
Is diagnosis code No. C1802 set?
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Go to Step 3.
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This diagnosis is complete.
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STEP 3. Check for diagnosis codes.
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Check if diagnosis code(s) other than No. C1802 is set.
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Q.
Is the diagnosis code set?
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Follow the relevant diagnosis code procedure, and then go to Step 7.
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Go to Step 4.
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STEP 4. Use M.U.T.-III to confirm a diagnosis code of other systems.
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Check if the diagnosis code is set in the FCM-ECU (Refer to GROUP 54A - FCM-LS,
Troubleshooting ).
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Q.
Is the diagnosis code set?
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Follow the relevant diagnosis code procedure. Then go to Step 7.
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Go to Step 5.
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STEP 5. Use M.U.T.-III to check a data list of FCM-ECU.
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Check the data list of FCM-ECU. (Refer to GROUP 54A - FCM-LS, Troubleshooting,
Data List Referrence Table
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- Item No.23: Vehicle speed
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Q.
Is the check result normal?
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Go to Step 6.
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Replace the laser radar (FCM-ECU) (Refer to GROUP 54A - FCM-LS, Laser
Radar ). Then go to Step 7.
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STEP 6. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the set diagnosis code.
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(2)Ignition switch: "LOCK" (OFF)
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(4)Drive the vehicle at 35 km/h or more.
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Q.
Is diagnosis code No. C1802 set?
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Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to ).
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction ).
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STEP 7. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the set diagnosis code.
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(2)Ignition switch: "LOCK" (OFF)
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(4)Drive the vehicle at 35 km/h or more.
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Q.
Is diagnosis code No. C1802 set?
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Return to Step 3.
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This diagnosis is complete.
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