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DTC C1786: System fail detected (T/M)
 
 
cautionWhen the ACC/FCM-ECU is replaced, calibrate the radar (refer to ).
 
 
OPERATION
The ACC/FCM-ECU receives system fault information from the TCM.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITION
Check Conditions
  • More than 2 seconds have passed since the ignition switch was turned to "ON" position.
  • ACC/FCM-ECU power voltage is more than 9 volts and is less than 18 volts.
Judgment Criterion
  • A signal, which indicates an abnormal transmission system, is received from the TCM.
 
 
PROBABLE CAUSES
  • Malfunction of CVT system
  • Malfunction of ACC/FCM-ECU

 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), check the CVT system DTC.
(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) Turn the ignition switch to the "ON" position.
(3) Using scan tool (M.U.T.-IIISE), perform CVT system DTC (Refer to GROUP 23A - Diagnosis <CVT>, Diagnostic Function ).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is any DTC set?
Repair the CVT system (Refer to GROUP 23A - Diagnosis <CVT>, Diagnostic Trouble Code Chart ).
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Is DTC C1786 set?
Replace the ACC/FCM-ECU (Refer to ).
It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).