Hyundai Ioniq: Low Voltage DC/DC Converter (LDC) / Repair procedures

Hyundai Ioniq (AE) 2017-2025 Service Manual / Hybrid Control System / Low Voltage DC/DC Converter (LDC) / Repair procedures

Removal
   
•
Be sure to read and follow the "General Safety Information and Caution" before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries.
•
Be sure to shut off the high voltage before doing any work related with the high voltage system (Refer to "High Voltage Shut-off Procedure"). Failure to follow the safety instructions may result in serious electrical injuries.
1.
Shut off the high voltage circuit.
(Refer to Hybrid Control System - "High Voltage Shutoff Procedure")
2.
Remove the air cleaner assembly and air duct.
(Refer to Engine Mechanical System - "Air Cleaner")
3.
Remove the ECM & TCM bracket assembly.
(Refer to Engine Control/Fuel System - "Engine Control Module")
4.
Drain the coolant of hybrid motor cooling system.
(Refer to Hybrid Motor Cooling System - "Coolant")
5.
Remove the HPCU protector (A) after loosening the mounting bolts.

6.
Disconnect the motor power cable connector (A) and HSG power cable conector (B).

7.
Disconnect the power cable (A) [↔ High voltage battery system assembly] and power cable (B) [↔ HSG & Electric A/C compressor].

   
•
Remove the inverter power cale in the follwing order.

8.
Disconnect the HCU & inverter (MCU) connector (A).

9.
Disconnect the coolant outlet hose & pipe (A) after loosening the mounting bolt.

10.
Disconnect the LDC power output cable (A) and LDC ground (-) cable (C) after loosening the mounting bolt and nut.

11.
Remove the HPCU (A) after loosening the mounting bolts.

Installation
   
•
Be sure to read and follow the "General Safety Information and Caution" before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries.
1.
Install the LDC in the reverse order of removal.
HPCU Installation bolt :
19.6 - 29.4 N.m (2.0 - 3.0 kgf.m, 14.5 - 21.7 lb-ft)
LDC Power otulet cable installation bolt :
3.9 - 5.9 N.m (0.4 - 0.6 kgf.m, 2.9 - 4.3 lb-ft)
LDC Ground cable installation bolt :
3.9 - 5.9 N.m (0.4 - 0.6 kgf.m, 2.9 - 4.3 lb-ft)
2.
Refill the hybrid motor cooling system coolant and perform air bleeding by using the GDS.
(refer to Hybrid Motor Cooling System - "Coolant")
   
•
Perform HCU Variant Coding and Engine Clutch / Motor Resolver learning after replacing the HPCU.
HCU Variant Coding
1.
Turn the ignition switch OFF.
2.
Connect the KDS / GDS to Data Link Connector (DLC).
Turn the ignition switch ON.
3.
Select "Vehicle, Model year, Engine, System".
4.
Select "Vehicle S/W Management".
5.
Select "HCU Variant Coding".

Engine clutch/motor resolver adaptation
1.
Turn the ignition switch OFF.
2.
Connect the KDS / GDS to Data Link Connector (DLC).
Turn the ignition switch ON.
3.
Select "Vehicle, Model year, Engine, System".
4.
Select "Vehicle S/W Management".
5.
Select "Engine clutch/motor resolver adaptation.".

    Schematic diagrams

    S..

    Power Cable

    ..

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