GROUP
ELE

MODEL
2019MY~ Niro EV
(DE EV)

NUMBER
234

DATE
April 2021

TECHNICAL SERVICE BULLETIN
SUBJECT:

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

This bulletin provides the procedure to inspect and repair the EV motor drive unit and reduction
gear on some 2019MY~ Niro EV (DE EV) vehicles produced from December 5, 2018, which may
exhibit an abnormal rumble noise while driving (refer to noise sample videos below). The rumble
noise may be heard repeatedly when the traction motor is operating, while driving slowly in “D”
range, or when slowly accelerating/decelerating between 0~25 mph. To correct this concern,
follow the procedure outlined in this bulletin to inspect and repair the traction motor and/or
reduction gear.
Refer to the videos below for examples of abnormal motor and reduction gear noise:
Video: Abnormal
Motor Noise in Vehicle

Video: Abnormal
Reduction Gear Noise in Vehicle

Note: Ensure to not mistake the abnormal noises for the normal noise of the EV motor in
the vehicle. Refer to the video below for an example of normal EV motor noise.
Video: Normal
Motor Noise

Drive Motor & Reduction Gear Assembly

Printed TSB copy is for reference only; information may be updated at any time.
Always refer to KGIS for the latest information.
Circulate To:

X General Manager


X Service Advisors


X Technicians


X Service Manager


X Parts Manager


X Body Shop Manager  Fleet Repair


Page 2 of 17

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

SUBJECT:

Flow Charts:

OK
Test drive
(Check noise)

Replace motor/roll mount
brackets (2 types)
and bolts*

Test drive
(Check noise)

KIT replacement

Vehicle out

Noise generation

*Use Kit A or Kit B depending on production date. Refer to Parts table for details.

Remove traction
motor/reduction gear

Inspect
traction motor/
reduction gear

Inspect traction motor/reduction
gear and assemble vertically

OK

Assemble traction
motor/reduction
gear vertically

Test drive
(Check noise)

Noise generation

Replace traction motor
or reduction gear

Test drive
(Check noise)

Replace traction motor or reduction gear

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 3 of 17

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

SUBJECT:

Preparation Procedure:
BEFORE beginning work:
• Refer to all safety precautions found in the applicable Shop Manual on KGIS, “General Safety
Information and Caution”
• Disconnect the negative (-) battery terminal.
• Perform the high voltage cut-off work by referring to the “General Information High Voltage
Shut-off Procedures” in the applicable Shop Manual on KGIS.

WARNING
• When working on the high voltage system, make sure that you are familiar and
comply with the “Safety Precautions, Cautions and Warnings” in the applicable
Shop Manual on KGIS.
• If you do not comply with the instructions, serious accidents due to electric shock
or leakage may occur.
• When working on the high voltage system, make sure to cut off the high voltage
first according to the “High Voltage Cut-off Procedure” in the applicable Shop
Manual on KGIS.
• Be sure to wait for at least 3 minutes after disconnecting the cable.
1.

Disconnect
the
service
interlock
connector (A).
If it is difficult to disconnect the service
interlock connector do the following steps:

A

1) Turn OFF the ignition switch and
disconnect the negative (-) cable of the
12V auxiliary battery.
2) Remove the trunk luggage board and
the rear seat, referring to the “Body
(Interior and Exterior) → Rear Seat →
Rear Seat Assembly → Repair
procedures” chapter in the applicable
Shop Manual on KGIS.
3) Remove the service plug cover (B).
4) Remove the service plug (C).

B

C

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 4 of 17

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

SUBJECT:

Roll Mount/Motor Support Bracket & Bolt Replacement Procedure:
1. Remove the under cover by referring to
the “Traction Motor System → Motor &
Reduction Gear → Under Cover →
Repair procedures” chapter in the
applicable Shop Manual on KGIS.
2.

Support the drive motor (D) / reduction
gear (E) assembly with a jack.
Note: For more details on removal and
disassembly steps, refer to the following
chapters in the applicable Shop Manual
on KGIS:
• “Traction Motor System → Motor &
Reduction Gear → Motor & Reduction
Gear Mounting → Repair procedures”
• “Traction Motor System → Motor &
Reduction Gear → Motor & Reduction
Gear Assembly → Repair procedures”

3.

Loosen the roll mount bracket retaining
bolts (F and G) and remove the roll
mount bracket.

E
/
E

D
/
E

F

G

4.

Replace the roll mount bracket (H) with
the new improved part.
Torque specification:
• Bolt (F): 79.6 – 94.1 lb.ft
(107.9 – 127.5 N.m, 11.0 – 13.0 kgf.m)
• Bolt (G): 47.0 – 61.5 lb.ft
(63.8 – 83.4 N.m, 6.5 – 8.5 kgf.m)
Old Part

H

New Part

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 5 of 17

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

SUBJECT:

5.

Lower vehicle on lift and place a jack
under the motor.

6.

Loosen the three (3) motor support
bracket nuts (I, J) and bolt (K) and remove
the motor support bracket.

I
K

Torque specification (for reinstallation):
• Nut (I): 57.9 – 72.4 lb.ft
(78.5 – 98.1 N.m, 8.0 – 10.0 kgf.m)
• Nut (J), Bolt (K): 43.4 – 54.3 lb.ft

(58.9 – 73.6 N.m, 6.0 – 7.5 kgf.m)

7.

J

Loosen the two (2) wire harness
retaining bolts (L) and the two (2) Electric
Water Pump (EWP) retaining bolts (M).
Detach the wire harness and EWP from
the motor support bracket.

L

M

8.

Loosen the five (5) motor support bracket
retaining bolts (N).
Note:
• Lower the jack supporting the motor
and loosen the bolt on the upper-left
side.
• Move the water hose and hold it up

while accessing the upper-left bolt.

N

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 6 of 17
SUBJECT:

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

9a. Remove the mass (O) from the new motor
support bracket.
9b. Install the new motor support bracket to
the vehicle.
Torque specification:
• Bolts (N): 57.9 – 72.4 lb.ft
(78.5 – 98.1 N.m, 8.0 – 10.0 kgf.m)

O

10. Install the mass (O) to the upper side of
the new motor support bracket as shown.

 IMPORTANT
Install with the mass protrusion
pointing towards the motor.

O

11. Raise the vehicle on the lift.

D
2

Remove the six (6) drive motor (D) and
reduction gear (E) connecting bolts (P).

 NOTICE
Bolts are numbered in order of
tightening
sequence
when
reinstalling.

6

3
1

5

E

P
4

6

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 7 of 17
SUBJECT:

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

12. Use a universal joint and extension (Q)
when loosening bolts No.4 and No.6.

Q

13. Remove the junction box (R) when
removing bolts No.7 and No.8.

8

R

7

Note: Refer to the “Battery Control
System → High Voltage Distributing
System → High Voltage Junction Box →
Repair procedures” chapter in the
applicable Shop Manual on KGIS.
14. When removing the junction box, use a
4mm Allen wrench for the OBC bolts (S),
and 10mm Hex wrench for the EPCU
bolts (T).

S

 IMPORTANT
• Comply with the specified
torque when reinstalling.
• Pay special attention to
tighten bolts in the correct
position, not slanted.

T

Torque specification:
• Bolts (S): 2.9 – 4.3 lb.ft
(3.9 – 5.9 N.m, 0.4 – 0.6 kgf.m)
• Bolts (T): 6.5 – 7.2 lb.ft
(8.8 – 9.8 N.m, 0.9 – 1.0 kgf.m)
Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 8 of 17
SUBJECT:

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

15. Mark the new drive motor and reduction
gear connecting bolts (P*) with a red
Sharpie (or similar marker) as shown to
distinguish them from the old ones.

P*

16. Reinstall the motor and reduction gear
using the new bolts in reverse order of
removal.
Note: Tighten to the specified torque in
the numbered order shown.

2

P*
6

3

Torque specification:
• 65.8 – 71.6 lb.ft
(89.3 – 97.1 N.m, 9.1 – 9.9 kgf.m)

1

5

Note: Tighten bolts 1 - 6 from underneath
vehicle.

4

6

Note: Tighten bolts 7 and 8 from above.
Torque specification:
• 65.8 – 71.6 lb.ft
(89.3 – 97.1 N.m, 9.1 – 9.9 kgf.m)

8
7

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 9 of 17

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

SUBJECT:

17. Assemble all parts in reverse order of
disassembly.
18. Test drive vehicle at least 2 times, and
verify normal noise/operation.
•

If the noise is no longer present, the
repair is complete.

•

If there is still a rumble noise from the
EV motor, proceed with the ‘Motor
and Reduction Gear Removal
Procedure’ outlined below.

Motor and Reduction Gear Removal Procedure:
1. Remove the motor and reduction gear
assembly from the vehicle by referring to
the “Traction Motor System → Motor &
Reduction Gear → Motor & Reduction
Gear Assembly → Repair procedures”
chapter in the applicable shop manual on
KGIS.
2.

Proceed to the ‘Motor and Reduction
Gear
Inspection
and
Vertical
Reassembly’ procedure on page 10.

Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.

TSB: ELE234 Niro EV (DE EV) April 2021

Page 10 of 17
SUBJECT:

DRIVE UNIT INSPECTION & REPLACEMENT
FOR EV MOTOR RUMBLE NOISE

Motor and Reduction Gear Inspection and Vertical Reassembly:
1. With the removed drive motor/reduction
gear assembly on a table, disconnect the
drive motor from the reduction gear.

 NOTICE
Plug a cap (U) into the drive shaft
hole to prevent oil from spilling out.

U

Drive Motor Noise Inspection:

1.

Rotate the drive motor shaft (V) to check
for a rumble noise.
1. Connect a 5mm hexagon tip to the
taper plug at the end of the shaft.

V

2. Start a counterclockwise rotation by
gently turning with your hands.
3. Use a power tool to increase the
speed of rotation.

CAUTION
Strong
initial
torque
damage the taper.