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Home >> Hyundai >> 2021 >> Ioniq Hybrid SEL >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> HCU/Low Dc-Dc Converter Diagnosis (HEV) >> DTC P1744: Transmission Engine Clutch System Performance >> System Inspection

System Inspection

  1. Remove the undercover below the vehicle and check the connector of the engine clutch actuator (HCA) for normal connection and corrosion.
    • If the connector is connected incorrectly, connect the connector correctly and check the system.
    • Check the connector terminal on the HCA for corrosion.
    • If there is a leak from the engine clutch system, replace the part where the leak is occurring.
    • If the connector is connected correctly and there is no corrosion, carry out No. 2 item.

      Turn off the ignition switch and back on. Set HEV Ready and place the gear lever to P position. Using GDS, perform (1) Removal of air from engine clutch hydraulic pressure line-> (2) Engine Test On.

  2. Select 'Engine Test On' in the 'Optional Function.' Then, compare the engine speed and motor speed on the Current Data.
    • If the motor speed cannot be captured, clear the DTC. Then wait for 5 minutes to see if the DTC P1744 returns after placing the gear lever to P position and running the engine (operate the accelerator, air conditioner, etc.). If P1744 does not return, go to Step  3. If it returns, go to Step  4.
    • If the motor speed is captured, it indicates that the engine clutch cannot be open. Go to Step  4.
  3. Actuate 'Engine clutch engagement test' on the Current Data and wait for 30 sec. Then, compare the engine speed and motor speed.
    • Wait for 8 sec. after actuating the Engine clutch engagement test. If the engine speed and motor speed are in sync, it indicates that the system works properly. Go to "VERIFICATION OF VEHICLE REPAIR ".
    • If the engine speed and motor speed are out of sync after 8 sec. of the actuation, go to Step  4 and inspect the abnormal system.
  4. Dissemble the engine clutch system and inspect hardware units (clutch cover, disk, actuator, hydraulic pressure line, CSC, reserve tank and line). Replace relevant component(s) as necessary. After replacing it, one must carry out (1) Initialization of the engine clutch initialization line learning and diagnosis information →(2) Removal of air from engine clutch hydraulic pressure line → (3) Engine clutch/Motor Resolver Adaptation → (4) Stabilization of the engine clutch hardware transfer torque in order using the GDS.

    * If the engine clutch cover and disk are not replaced, it is not necessary to carry out (4) Stabilization of the engine clutch hardware transfer torque.

    * In case the SOC is below 35%, when the shift gear is left at P in the ignition switch "ON"/HEV Ready status, the engine will operate and the SOC will be charged.

    * When carrying out air bleeding from the hydraulic line of the engine clutch after replacing the engine clutch system, the function will be carried out normally only when the temperature of the hydraulic oil (brake oil DOT 3) is at room temperature (over 20°C).

    NOTE:
    • Method to confirm the reasons and respond when the optional function of the engine clutch fails
      • If the optional function of the engine clutch fails, check HCU Error Code and LuK Error Code on the screen of the diagnostic tool and carry out inspection items.
  1. HCU Error Code 
    G13841269Courtesy of HYUNDAI MOTOR AMERICA
  2. LuK Error Code 
    G13841270Courtesy of HYUNDAI MOTOR AMERICA
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