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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.
 
 
DIAGNOSTIC FUNCTION AND TROUBLE JUDGMENT
This DTC is set when the abnormality below is detected:
  • The ECU receives an FCM deactivation signal from the ASC-ECU.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the FCM/LDW/AHB-ECU
  • Defective ASC circuit system (automatic braking illumination circuit)
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), read the other system DTC.
Check if DTC C1800 or C1801 is set in the ASC-ECU.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(4) Check if the DTC is set.
Is the DTC set?
Troubleshoot the ASC-ECU (Refer to GROUP 35C - Troubleshooting ).
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), read the DTC again.
Check again if the DTC other than code No. C1798 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?
Troubleshoot the relevant DTC (Refer to ).
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-IIISE), read the DTC 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 ).