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DTC C1771: Radar calibration fail (Upper)
 
 
cautionWhen the ACC/FCM-ECU is replaced, calibrate the radar (refer to ).
 
 
OPERATION
ACC/FCM-ECU monitors the radar calibration.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITION
Check Conditions and judgment Criterion
  • Ignition switch is "ON" position.
  • Radar calibration is in progress.
  • The radar calibration is performed while the ACC/FCM-ECU is tilted by 3 degrees or more to the upper direction.
noteA DTC is not set as a historic fault.
 
 
PROBABLE CAUSES
  • Dirt or foreign material on the radar
  • Improperly installed ACC/FCM-ECU
  • Malfunction of ACC/FCM-ECU
  • Unfavorable vehicle condition, such as too heavy load, improper wheel alignment or tire punctuation

 
 
DIAGNOSIS
STEP 1. Check the radar for dirt or foreign material.
Is the check result normal?
Go to Step 2.
Wipe off the dirt or foreign material from the ACC/FCM-ECU's radar. Then go to Step 3.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check the data list.
(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), check the data list (Refer to data list reference table ).
  • Item No.70: Vertical angle offset (Service)
noteThe deviation angle cannot be corrected while checking the data list because the value in this data list will be updated after the radar calibration is performed.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Replace the ACC/FCM-ECU (Refer to ).
Repair the improperly installed ACC/FCM-ECU and ACC/FCM-ECU bracket or deformation of the body, and install them again (Refer to ). Then go to Step 3.
 
STEP 3. ACC/FCM-ECU radar calibration.
Perform calibration of ACC/FCM-ECU radar calibration (Refer to ).
Has the calibration succeeded?
Go to Step 4.
Go to Step 2.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check again if the DTC is set in the ACC/FCM-ECU.
(1) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(2) Check that the DTC is set again.
Is DTC C1771 set?
Replace the ACC/FCM-ECU (Refer to ).
This diagnosis is complete.