TSB_CHA098_R3

GROUP
CHA
MODEL
2014-2019MY
All Listed Models
NUMBER
098 (Rev 3, 08/07/2020)
DATE
August 2019
TECHNICAL SERVICE BULLETIN
SUBJECT:
IBAU SYSTEM REPAIR FOR NOISE AND AIR BLEEDING
 NOTICE
This bulletin has been revised to include additional information. New/revised
sections of this bulletin are indicated by a black bar in the margin area.
This bulletin provides the repair procedure for the Integrated Brake Actuation Unit (iBAU) system on
some 2014-2019MY EV/Hybrid/Plug-In Hybrid vehicles listed (see table), which may exhibit a “Honking”
(Hissing) noise due to air remaining in the brake fluid system. Perform the air bleeding procedure
outlined in this bulletin for the “Honking (Hissing) noise” concern when operating the brake pedal. Note:
It is not recommended to replace the iBAU, Pressure Source Unit (PSU) and/or other related Active
Hydraulic Boost (AHB) brake system components for this noise concern.
iBAU Repair Application Table
iBAU
PSU
Model Vehicle
Model Year
Niro (DE HEV/PHEV)
2017-2019MY
Optima (TF HEV)
2014-2016MY
Optima (JF HEV/PHEV)
2017-2019MY
Soul ( PS EV)
2015-2019MY
Audio Media File: Click for “Honk” sample noise.
Video Media File: Click for “IBAU Air Bleeding” procedure.
Air remaining in
the brake system.
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 
X Fleet Repair

Page 2 of 3
IBAU SYSTEM REPAIR FOR NOISE AND AIR BLEEDING
SUBJECT:
Comparison between General and iBAU brake systems:
Integrated Brake Actuation Unit (iBAU):
When a driver presses the brake pedal, the iBAU delivers brake fluid charged in the PSU to the
calipers by opening a valve. When pressing the brake pedal, high pressure brake fluid passes
through the internal iBAU valve. Then, the valve operating sound “click” will be heard.
Pressure Source Unit (PSU):
The PSU continuously charges and stores brake fluid at high pressure (2,321 – 2,611 psi., 160180 Bar) by operating the PSU motor. When a driver presses the brake pedal, the brake fluid is
then delivered to the calipers through the iBAU valve. After pressing the brake pedal, the
normal PSU motor operating sound “grrr” will be heard while it recharges the lowered pressure.
Air Bleeding Procedure:
 NOTICE
The iBAU consists of 3 brake fluid lines in total (low/high pressure and pedal
simulator lines), therefore, air bleeding should be made sequentially following the
procedure below.
Procedure
iBAU/AHB Brake System Bleeding
1.
Step
Repair
iBAU ECU
1
Low Pressure and Simulator Fluid Lines
OFF
2
High Pressure Brake Fluid Line
ON
3
Fluid Circulation Mode with KDS
ON
Refer to the “Brake System → Brake
Bleeding Procedure” chapter in the
applicable Shop Manual on KGIS.



Air Bleeding Tool Installation
Procedure
AHB Brake System Bleeding
(Steps 1, 2 and 3)
Air Bleeding Tool Removal
Procedure
Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.
TSB: CHA098 (Rev 3) Multiple Models August 2019
Page 3 of 3
IBAU SYSTEM REPAIR FOR NOISE AND AIR BLEEDING
SUBJECT:
AFFECTED VEHICLE RANGE:
Model
Production Date Range
Niro (DE HEV)
2017 - 2019MY
Niro (DE PHEV)
2018 - 2019MY
Optima (TF HEV)
2014 -2016MY
Optima (JF HEV)
2017 - 2019MY
Optima (JF PHEV)
2017 - 2019MY
Soul (PS EV)
2015 - 2019MY
REQUIRED TOOL:
Tool Name
Figure
Comments
Located in
SST Cabinet Drawer #7
SST 09580 3D100
WARRANTY INFORMATION:
N Code: Q55 C Code: ZZ3
Model
Claim
Type
Causal
P/N
Niro
(DE)
P/HEV
58500
G5400
Optima
(TF)
HEV
58500
4U700
W
Qty.
58500
A8450
Soul
(PS)
EV
58500
E4100
Labor Op
Code
Op
Time
Replacement
P/N
Qty.
58700A1H
1.4
M/H
N/A
0
iBAU System
AHB Brake System
Bleeding
0
Optima
(JF)
P/HEV
Repair
Description
iBAU System
AHB Brake System
Bleeding
iBAU System
AHB Brake System
Bleeding
 NOTICE
Warranty claims submitted for Integrated Brake Actuation Unit (iBAU) assemblies for
unnecessary replacement will be subject to warranty chargeback.
Printed TSB copy is for reference only; information may be updated at any time. Always refer to KGIS for the latest information.
TSB: CHA098 (Rev 3) Multiple Models August 2019