KIA Niro: The Power Relay Assembly
Description
The Power Relay Assembly (PRA) consists of the positive and negative main relays, pre-charge relay, pre-charge resistor and battery current sensor. It is located inside the battery pack assembly and controls the high voltage power circuit between the high voltage battery and inverter by the control signal of BMS ECU.
PRA Operation Sequence
Circuit Diagram
Removal
Warning
- 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 read and follow the "High Voltage Shut-off Procedures" before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries
- Turn ignition switch OFF and disconnect the negative (-) battery cable.
- Shut off the high voltage circuit.
(Refer to Hybrid Control System - "High Voltage Shut-off Procedures")
- Remove the power relay assembly.
(Refer to High Voltage Battery System - "Power Relay Assembly")
- Remove the main relay (A).
Main Relay (+)
Main Relay (-)
Installation
Warning
- 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 read and follow the "High Voltage Shut-off Procedures" before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries.
- Install the main relay in the reverse order of removal.
Inspection
Warning
- 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 read and follow the "High Voltage Shut-off Procedures" before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries.
Checking for Welding in the High Voltage Main Relay
Using KDS service data to check for main relay weld damage
- Connect the KDS to the Data Link Connector (DLC).
- Turn the ignition switch ON.
- Check the BMS weld damage state in the KDS service data.
Using a Multimeter to measure weld damage
- Shut off the high voltage.
(Refer to "High Voltage Shut-off Procedures")
- Remove the high voltage battery rear cover.
(Refer to "High Voltage Battery System - "Case")
- Remove the inlet cooling duct.
(Refer to Hybrid Control System - "Cooling Duct")
- Measure the high voltage main relay resistance and check for signs of weld damage.
Specification : ∞Ω (20ºC (68ºF))
High voltage main relay (-) switch resistance
- Shut off the high voltage.
(Refer to "High Voltage Shut-off Procedures")
- Remove the high voltage battery rear cover.
(Refer to "High Voltage Battery System - "Case")
- Remove the inlet cooling duct.
(Refer to Hybrid Control System - "Cooling Duct")
- Measure the resistance between the high voltage power terminal (-) and the inverter power terminal (-).
Circuit inspection (Relay ON)
Warning
Inspect the high voltage main relay (-) activated by KDS.
- Connect the KDS to the Data Link Connector (DLC).
- Turn the ignition switch ON.
- Activate the main relay by using "Actuation Test" on the KDS as shown in the illustration below.
Warning
When the relay is ON, there is a relay operation sound.
High Voltage Main Relay Coil Resistance
- Shut off the high voltage.
(Refer to "High Voltage Shut-off Procedures")
- Remove the power relay assembly.
(High Battery System - "Power Relay Assembly")
- Check for continuity between the terminals using an ohmmeter.
READ NEXT:
High Voltage Battery Cooling
Component
Location
Cooling Fan #1
Cooling Fan #2
Main High Voltage Battery Cooling Duct (Inlet)
Main High Voltage Battery Cooling Duct (Outlet)
Sub High Voltage Battery Cooling Duct (Inlet)
Sub High Voltage Battery Cooling Duct (Ou
Cooling Fan - Components and components location
Components
Cooling Fan #1
BLDC Motor
Main Connector
Cooling Fan #2
BLDC Motor
Main Connector
Removal
Warning
Be sure to read and follow the "General Safety Information and
Caution" before doing any work re
Cooling Fan Repair procedures
Installation
Warning
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
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Display and control
You can see the status of the Highway Lane Change Assist function operation in the Driving Assist view on the cluster.
Refer to "LCD display".
Highway Lane Change Assist function will be displayed as below depending o
HLA (Hydraulic Lash Adjuster)
With the HLA filled with engine oil, hold A and press B by hand.
If B moves, replace the HLA.
Reassembly
Warning
Thoroughly clean all parts to be assembled.
Before installing the parts, apply fresh engine oil to all
sliding
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