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DTC C1798 FCM control disabled (ASC)
 
 
caution
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
FCM/LDW/AHB-ECU communicates with the ASC-ECU via the CAN bus lines.
 
 
DTC SET CONDITION
This DTC is set when the abnormality below is detected:
  • The ECU receives an FCM deactivation signal from the ASC-ECU.
 
 
PROBABLE CAUSES
  • Malfunction of the FCM/LDW/AHB-ECU
  • Defective ASC circuit system (automatic braking illumination circuit)
 
 
DIAGNOSIS
STEP 1. Check the scan tool other system DTC.
Check if DTC C1800 or C1801 is set in the ASC-ECU.
Is the DTC set?
Troubleshoot the ASC-ECU.
Go to Step 2.
 
STEP 2. Check the scan tool DTC.
Use scan tool to check that any DTC other than DTC C1798 is set in FCM/LDW/AHB-ECU.
Is the DTC set?
Troubleshoot the relevant DTC (Refer to ).
Go to Step 3.
 
STEP 3. Check whether the DTC is set again.
Check again if the DTC is set in the FCM/LDW/AHB-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the FCM/LDW/AHB-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).