Kia Niro: Low Voltage DC/DC Converter (LDC) / Repair procedures

Kia Niro 2017 (DE HEV) Service Manual / Service Highlight / 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.

Hybrid Power Control Unit (HPCU)

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).

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.

LDC power (12V) output cable mounting nut :

10.8 - 13.7 N·m (1.1 - 1.4 kgf·m, 7.9 - 10.1 lb·ft)

LDC ground cable mounting bolt :

7.8 - 11.8 N·m (0.8 - 1.2 kgf·m, 5.8 - 8.7 lb·ft)

11.

Remove the HPCU (B) after looening the mounting bolts.

HPCU mounting bolt :

21.6 - 23.5 N·m (2.2 - 2.4 kgf·m, 15.9 - 17.4 lb·ft)

12.	Remove the coolant hose & pipe (A) from the HPCU.

13.

Remove the reservoir (B) after loosening the mounting bolts.

Reservoir mounting bolt :

3.9 - 5.9 N·m (0.4 - 0.6 kgf·m, 2.9 - 4.3 lb·ft)

Hybrid Power Control Unit (HPCU) Tray

1.	Remove the hybrid power control unit. (Refer to Hybrid Control System - "Hybrid Power Control Unit (HPCU)")

Remove the hybrid power control unit tray (A) after loosening the mounting bolts.

Hybrid Power Control Unit (HPCU) tray mounting bolt :

21.6 - 23.5 N·m (2.2 - 2.4 kgf·m, 15.9 - 17.4 lb·ft)

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.

•	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.	Install the LDC in the reverse order of removal.

2.	Refill the hybrid motor cooling system coolant and perform air bleeding by using the KDS/GDS. (refer to Hybrid Motor Cooling System - "Coolant")

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Kia Niro: Low Voltage DC/DC Converter (LDC) / Repair procedures

Schematic diagrams

Hybrid Motor Assembly

Other information: