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DTC C1805 FCM/LDW/AHB Malfunction
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
OPERATION
The ASC-ECU communicates with the FCM/LDW/AHB-ECU via CAN bus lines.
 
 
 
DTC SET CONDITIONS
If the ASC-ECU receives an abnormal signal from the FCM/LDW/AHB-ECU with the FCM activated, it will set the DTC.
 
 
 
PROBABLE CAUSES
  • Wiring harness or connector failure of CAN bus line
  • FCM/LDW/AHB-ECU malfunction
  • ASC-ECU malfunction
 
 
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
Use scan tool (M.U.T.-IIISE) to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check other system DTC.
Check that any DTC other than DTC C1798 is set in the FCM/LDW/AHB-ECU.
Is any DTC set?
Troubleshoot the relevant DTC (Refer to GROUP 54A - FCM/LDW/AHB-ECU ).
Go to Step 3
 
STEP 3. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
Is DTC C1805 set?
Replace the FCM/LDW/AHB-ECU (Refer to GROUP 54A - FCM/LDW/AHB-ECU ) and then go to Step 4.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 4. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
Is DTC C1805 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
This diagnosis is complete.