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DTC C1621: Electronic Controlled Coupling Solenoid (Center) Protection
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
The AWC-ECU calculates the electronic control coupling (center) temperature by the information of the electronic control coupling (center) control amount, outside temperate, etc. If it is detected that the electronic control coupling (center) temperature becomes extremely high, the high fluid temperature warning is displayed on the warning indicator.
 
 
DTC SET CONDITION
This DTC is stored when the abnormality below is detected:
  • The control is suspended to protect the electronic control coupling (center).
 
 
PROBABLE CAUSES
  • Electronic control coupling (center) protection control status
  • Severe driving
  • Electronic control coupling (center) failure (clutch slippage, etc.)
  • Outside temperature signal failure
  • Wheel speed signal failure
  • Engine-related failure (engine speed signal failure)
  • Ignition off time signal failure

 
 
DIAGNOSTIC PROCEDURE
STEP 1. Check whether the DTC is stored again.
(1) To release the electronic control coupling (Center) protection control, leave the vehicle for 15 minutes or longer after the high fluid temperature warning on the warning indicator disappears.
(2) Erase the DTC.
(3) Carry out the test drive.
noteDo not carry out the severe test drive.
(4) Check if the DTC is stored.
Is DTC No.C1621 stored?
Go to Step 2.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
 
STEP 2. Scan tool (M.U.T.-III) CAN bus diagnostics.
Use scan tool (M.U.T.-III) to perform the CAN bus diagnosis.
Is the check result normal?
Go to Step 4.
Repair the CAN bus lines (Refer to GROUP 54C - Diagnosis, Can Bus Diagnostics Table ). After repairing the CAN bus line, go to Step 3 .
 
STEP 3. Check whether the DTC is stored again.
Is DTC No.C1621 stored?
Go to Step 4.
This diagnosis is complete.
 
STEP 4. Scan tool (M.U.T.-III) data list
Check the following data list (Refer to ).
  • Item No.12: Engine speed
Is the check result normal?
Go to Step 5.
Perform the troubleshooting for the engine (Refer to GROUP 13A - Diagnosis, Diagnostic Trouble Code Chart ).
 
STEP 5. Scan tool (M.U.T.-III) data list
Check the following data list (Refer to ).
  • Item No.18: FL Wheel speed sensor
  • Item No.19: FR Wheel speed sensor
  • Item No.20: RL Wheel speed sensor
  • Item No.21: RR Wheel speed sensor
Is the check result normal?
Go to Step 6.
Perform the ASC DTC (Refer to GROUP 35C - Diagnosis, Diagnostic Trouble Code Chart ).
 
STEP 6. Scan tool (M.U.T.-III) data list
Check the following data list (Refer to ).
  • Item No.34: Ambient temperature (CAN input)
  • Item No.35: Ignition off time (CAN input)
Is the check result normal?
Go to Step 7.
Perform the troubleshooting for the ETACS (Refer to GROUP 54A - Diagnosis, Diagnostic Trouble Code Chart ).
 
STEP 7. Check of the electronic control coupling (Center)
Refer to GROUP 27C - On-vehicle Service .
Is the check result normal?
Go to Step 8.
Replace the electronic control coupling (center). (Refer to GROUP 27C - Electronic control coupling ).
 
STEP 8. Check whether the DTC is stored again.
(1) To release the electronic control coupling protection control, leave the vehicle for 15 minutes or longer after the high fluid temperature warning on the warning indicator disappears.
(2) Erase the DTC.
(3) Carry out the test drive.
noteDo not carry out the severe test drive.
(4) Check if the DTC is stored.
Is DTC No.C1621 stored?
Replace the AWC-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).