GROUP

NUMBER

CAMPAIGN

Technical Service Bulletin

DATE

20-01-029H
MODEL(S)

July, 2020

Nexo (Fe)

FCU & HMU CONTROL LOGIC UPDATE
(SERVICE CAMPAIGN T5D)

SUBJECT:

 IMPORTANT

*** Dealer Stock and Retail Vehicles ***
Dealers must perform this Service Campaign on all affected vehicles prior to customer retail delivery
and whenever an affected vehicle is in the shop for any maintenance or repair.
When a vehicle arrives at the Service Department, access Hyundai Motor America's "Vehicle
Information Screen (VIS)" via WEBDCS to identify open Campaigns.
Description: This bulletin provides software update information related to the Fuel Cell control Unit
(FCU) and Hydrogen storage Management Unit (HMU) on certain NEXO (FE) vehicles. This update
revises the logic for Malfunction Indicator Light (MIL) ON related to the FCU and HMU.
Applicable Vehicles: Certain 2019 – 2020MY NEXO (FE)
GDS Information:
Event #
576
577

Description
FCU CONTROL LOGIC IMPROVEMENT
HMU CONTROL LOGIC IMPROVEMENT

Warranty Information:
Model

Op. Code

Operation

Op. Time

Causal Part

Nature

Cause

Nexo (FE)

90C073R0

FCU & MCU
UPGRADE

0.5 M/H

39930-M5110

I3A

ZZ3

NOTE 1: Submit Claim on Campaign Claim Entry Screen
NOTE 2: If a part is found in need of replacement while performing (Service Campaign T5C) and the
affected part is still under warranty, submit a separate claim using the same Repair Order. If the
affected part is out of warranty, submit a Prior Approval Request for goodwill consideration prior to
performing the work.

Circulate To: General Manager, Service Manager, Parts Manager, Warranty Manager, Service
Advisors, Technicians, Body Shop Manager, Fleet Repair

SUBJECT:

FCU & HMU CONTROL LOGIC UPDATE (SERVICE CAMPAIGN T5C)

Additional action required when updating the FCU ROM.
ECU Hardware
Application
ROM ID
(H/W) Number
Software (S/W) ID

Application ID

39930M5100

HFEFKNNPRS0-D000

FES1120RNL

1120RNL610

39930M5110

HFEFKNNPAS0-D000

FES1120RNV

1120RNV610

Remarks
N.A (Blue or
GL)
N.A (Limited or
GLS)

Using the GDS-M (Global Diagnostic System - Mobile), select S/W
Management > Systems> Fuel Cell Unit> System Identification. Check
which FCU ROM version is applied to the current vehicle.
If the current FCU ROM version is not 1120 before updating the FCU ROM,
then no further action is required.
If the current version of the FCU ROM was 1120 before the FCU ROM
upgrade, then perform the following procedure after completing the FCU
ROM upgrade.


Start the vehicle, allow it to enter ready mode, then turn the vehicle off,
and then within five seconds, restart it immediately. After completing
this start-stop-start sequence, clear all DTC’s.

Note: After completing the FCU ROM upgrade, if the vehicle is driven without performing the above
procedure a warning light MIL may illuminate at a later time.
When checking for DTC’s, if codes P315292 / P915392 are active, pending or in history it is
necessary to perform the following start-stop-start procedure.
 Start the vehicle, allow it to enter ready mode, then turn the vehicle off, and then within five
seconds, restart it immediately. After completing this start-stop-start sequence, clear all DTC’s.

TSB #: 20-01-029H

Page 2 of 11
SUBJECT:

FCU & HMU CONTROL LOGIC UPDATE (SERVICE CAMPAIGN T5C)

SUBJECT:

Service Procedure:
General Precautions:

NOTICE
Before performing the service procedure, verify that the GDS-M is charged above 50%.










If the vehicle has been in storage for several days, run the fuel cell a sufficient amount of
time to ensure that the 12 volt battery is fully charged.
Ensure that the 12 volt battery will not become discharged during the upgrade by turning off
all lights and accessories including heater/air conditioner, fan, audio, heated seats, rear
defroster, etc.
Do not leave the headlight switch in auto mode.
Before performing the upgrade, set the POWER button to the ON position. To set the
POWER button to the ON position, press the button two times without pressing the brake
pedal.
Do not start the Fuel Cell.
Do not turn OFF the POWER button during the upgrade.
Do not disconnect any cables connected to the vehicle or GDS-M during the upgrade.

NOTICE
Confirm your GDS-M has the most recent software version. If not, connect the GDS-M
Mobile to an Internet port, open the GDS-M home page and select “Internet Update”. Refer
to www.hyundaitechinfo.com if necessary.
If you encounter GDS-M related problems, call the GIT Helpline at 888-437-0308.
!

WARNING

If a GDS-M warning specifying low battery voltage appears, select the Back Button
,
then run the fuel cell or charge the 12 volt battery to ensure an adequate state of charge.
Turn the system power back on, and retry the FCU / HMU upgrade again.

TSB #: 20-01-029H

Page 3 of 11
SUBJECT:

SUBJECT:

FCU & HMU CONTROL LOGIC UPDATE (SERVICE CAMPAIGN T5C)

NOTICE
Before proceeding, check FCU version per instructions on page 2.
GDS-M Automatic Mode - FCU & HMU Upgrade Procedure
1.

Connect the external power to the GDSM.
Connect the VCI-II into the vehicle's DLC
connector, and check that the VCI-II is
powered on.

2.

Turn ON the vehicle system power by
pressing the POWER button two times
without pressing the brake pedal. DO NOT
start the fuel cell.

NOTICE
The ECU upgrade function on GDS-Mobile is operating in wireless communication as
Wi-Fi direct. It is possible to perform the upgrade via USB cable between GDS Mobile and
VCI-II.
Before starting the ECU upgrade, verify the GDS-M battery is sufficiently charged.
3.

Select ECU Upgrade after entering the
vehicle information.

TSB #: 20-01-029H

Page 4 of 11
SUBJECT:

SUBJECT:

FCU & HMU CONTROL LOGIC UPDATE (SERVICE CAMPAIGN T5C)

4.

Read the CAUTION section in the
Information tab.

5.

Select “Auto Mode”.

6.

For each system (FCU and HMU) select
ID Check.

FCU

HMU

FCU

HMU

If a pop-up window appears stating the
upgrade has already been completed,
select OK, no further work is needed.
Otherwise proceed to step 7.

7.

The GDS-M will recognize the current
vehicle ROM ID, and look for the upgrade
event. Select Upgrade.

For FCU, select the upgrade event:
576.FE - FCU CONTROL LOGIC
IMPROVEMENT

For HMU, select the upgrade event:
577.FE - HMU CONTROL LOGIC
IMPROVEMENT

TSB #: 20-01-029H

Page 5 of 11
SUBJECT:

SUBJECT:

8.

FCU & HMU CONTROL LOGIC UPDATE (SERVICE CAMPAIGN T5C)

Upgrade (1/2) will begin, and the progress
of the upgrade will appear on the bar
graph.

FCU

HMU

FCU

HMU

FCU

HMU

Upgrade (1/2) will occur until 100% is
reached on the bar graph.