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DTC C1771: Reflector Plate in the Uppermost
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
ACC-ECU monitors the radar calibration.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITION
This diagnostic trouble code is set when the abnormality below is detected:
  • The radar calibration is performed while the ACC/-ECU is tilted by 3.5° or more downwards.
 
 
PROBABLE CAUSES
  • Dirt or foreign material on the radar
  • Malfunction of wheel alignment
  • Distorted or deformed vehicle
  • Improperly installed ACC-ECU
  • Malfunction of ACC-ECU

 
 
DIAGNOSIS
STEP 1. Check the radar for dirt or foreign material.
(1) Wipe off the dirt or foreign material from the ACC-ECU's radar.
(2) Check whether the ACC-ECU is installed correctly (Refer to ).
Is the check result normal?
Go to Step 2
Repair the ACC-ECU (Refer to ). Then go to Step 2
 
STEP 2. Scan tool (M.U.T.-III) data list
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Check the following data list (Refer to ).
  • Item No.222: Current angle offset vertical
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 3
Correct the installation angle of the ACC-ECU to reinstall it (Refer to ). Then go to Step 3.
 
STEP 3. ACC-ECU’s radar calibration
Perform calibration of ACC-ECU’s radar calibration (Refer to ).
Has the calibration succeeded?
This diagnosis is complete.
Go to Step 4
 
STEP 4. Scan tool (M.U.T.-III) data list
Check the following data list (Refer to ).
  • Item No.222: Current angle offset vertical
Is the check result normal?
Go to Step 5
Correct the installation angle of the ACC-ECU to reinstall it (Refer to ). Then go to Step 3.
 
STEP 5. Check whether the diagnostic trouble code is set again.
Is diagnostic trouble code No.C1771 set?
Replace the ACC-ECU (Refer to ).
This diagnosis is complete.