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DTC C1806 ACC/FCM target deceleration signal
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
OPERATION
The ASC-ECU communicates with the ACC/FCM-ECU via CAN bus lines.
 
 
 
DTC SET CONDITIONS
If the ASC-ECU receives an abnormal signal from the ACC/FCM-ECU with the FCM activated (automatic braking applied), it will set the DTC.
 
 
 
PROBABLE CAUSES
  • Wiring harness or connector failure of CAN bus line
  • Malfunction of ACC/FCM-ECU
  • Malfunction of ASC-ECU
 
 
 
 
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 ).
 
STEP 2. Using scan tool (M.U.T.-IIISE), check other system DTC.
Use scan tool (M.U.T.-IIISE) to check whether any coding-related DTC (except DTC C2340) is set by ACC/FCM-ECU (Refer to GROUP 17 - Adaptive Cruise Control System (ACC)/Diagnostic trouble code chart ).
Is the diagnostic trouble code set?
Troubleshoot for the relevant Diagnostic trouble code.
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 C1806 set?
Replace the ACC/FCM-ECU (Refer to GROUP 17 - Adaptive Cruise Control System (ACC) ). 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 C1806 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
This diagnosis is complete.