GROUP
NUMBER
Campaign
Technical Service Bulletin
SUBJECT:
DATE
21-01-045H-1
MODEL(S)
September, 2021
Nexo (FE)
STACK COOLANT PUMP REPLACEMENT
(SERVICE CAMPAIGN T6A)
This TSB supersedes 21-01-045H by adding an updated coolant part number 00232-19080.
IMPORTANT
***** RETAIL*****
Dealers must perform this Service Campaign on all affected vehicles 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 "Warranty
Vehicle Information screen (VIS)” via WEBDCS to identify open Campaigns.
Description: Certain 2019MY Nexo vehicles may illuminate a check engine light due to a powertrain
related DTC P1D3D94 (Coolant Stack Pump – Motor or Internal Controller Malfunction) resulting in
reduced engine power due to cracking in the stack coolant pump rotor molding. This bulletin provides
replacement procedures related to the stack coolant pump.
Refer to the Fuel Cell System > Thermal Management System > Stack Coolant Pump section in the
Shop Manual, and then follow the procedures outlined in this bulletin whenever a vehicle with the
following symptoms is being diagnosed:
Check Engine Light illumination with powertrain related DTC P1D3D94.
Warning light message on the cluster indicating to safely park the vehicle.
Reduced engine power.
DTC Description:
P1D3D94 is set when there is a stack coolant pump internal controller malfunction, or the stack coolant
pump motor is inoperative.
Applicable Vehicles: Certain 2019MY Nexo (FE) vehicles.
Parts Information:
Part Name
Part Number
Stack Coolant Pump
25816-M5000QQH
Stack Coolant
00232-19080 (2L)
Figure
Qty.
1
N/A
10L (5EA)
Circulate To: General Manager, Service Manager, Parts Manager, Warranty Manager, Service
Advisors, Technicians, Body Shop Manager, Fleet Repair
SUBJECT:
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Warranty Information:
Model
Op. Code
Operation
Op.
Time
Causal Part
Causal
Code
Nature
Code
STACK COOLANT
1.8
25816ZZ1
I11
PUMP REPLACEMENT M/H
M5000QQH
NOTE 1: Submit Claim on Campaign Claim Entry Screen
NOTE 2: If a part that is not covered by this campaign is found in need of replacement while performing
this service campaign 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.
Nexo (Fe)
00D103R0
Service Procedure:
A. Stack Coolant Pump Replacement
1.
Ensure the Push Button Start Stop (PBSS) is
off, and the fuel stack is not in Ready Mode.
Wait at least 3 minutes before continuing
with the procedure.
2.
From the vehicle cargo area, remove the
floorboard and cargo tray to access the 12V
battery connector and high voltage safety
plug.
3.
Disconnect the auxiliary 12V battery
negative (-) connector.
NOTICE
4.
Be sure to record the radio presets
prior to battery disconnection.
Remove the metal shield to access the High
Voltage Safety Plug.
NOTE: Wear Personal Protective Equipment
(PPE) when working with the high voltage
system.
TSB #: 21-01-045H-1
Page 2 of 10
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5.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Follow the reference 1- 4 steps to remove
the orange high voltage safety plug.
Store the removed safety plug in a secure
location outside and away from the vehicle.
1
3
6.
Press down on the safety
plug lever
2
Pull the green safety plug
lock tab
4
Remove the safety plug
Remove the fuel cell stack room undercover.
Refer to the service manual section for
proper service procedure.
Fuel Cell System > Fuel Cell Stack > Fuel
Cell Stack Room Under Cover
7
Drain the stack coolant.
Refer to the service manual section: for proper service procedure.
Fuel Cell System > Thermal Management System > Stack Coolant
8.
Remove the air cleaner assembly.
Refer to the service manual section for proper
service procedure.
Fuel Cell System > Air Processing System
> Air Cleaner.
TSB #: 21-01-045H-1
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9.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Remove the Stack Trim Cover (A).
Refer to the service manual section for proper
service procedure.
Fuel Cell System > Air Processing System
> Fuel Cell Stack Cover.
10.
Remove the stack coolant ion filter as an
assembly (A). DO NOT remove filters from
canister.
To prevent loss of coolant from filter canister.
Insert a tapered plug into the upper hose fitting
on the filter canister then remove the lower
hose from filter canister and insert a tapered
plug into lower hose fitting on the filter
canister.
Refer to the service manual section for proper
service procedure.
Fuel Cell System > Thermal Management
System > Stack Coolant Ion Filter.
TSB #: 21-01-045H-1
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11.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Remove the stack coolant reservoir, (B) do not
allow coolant to drain out of reservoir.
Refer to the service manual section for
detailed service procedure.
Fuel Cell System > Thermal Management
System > Stack Coolant Reservoir Tank
12.
Remove the stack coolant pump outlet hose
(A).
A
Refer to the service manual section for
detailed service procedure.
Fuel Cell System > Thermal Management
System > Stack Coolant Pump
13.
Disconnect the stack coolant pump wiring
connector (B) and wiring clip (C).
B
C
14.
Disconnect the stack coolant pump inlet
hose clamp (D).
TSB #: 21-01-045H-1
D
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15.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Disconnect the stack coolant pump high
voltage cable connector (E).
E
(1) Remove the connector locking pin.
(2) Press on the 1st holding point.
(3) Insert a screwdriver into the 2nd holding
point and remove the high voltage
connector by pulling on the connector.
16.
1st Holding Point
Remove the stack coolant pump (F).
Tightening torque:
lb-ft
kgf.m
N.m
17.
2nd Holding Point
F
•15.2 - 16.6
•2.1 - 2.3
•20.6 - 22.6
Use shop compressed air to blow off any
coolant that may have dripped on the
junction connector when removing the stack
coolant pump.
TSB #: 21-01-045H-1
Page 6 of 10
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STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
B. Stack Coolant Pump Disassembly and Replacement
1.
Remove the stack coolant pump hose (G).
Remove the inlet and outlet hose (H).
G
NOTICE
Do not discard the stack coolant
pump hose. The pump hose will be
installed onto the replacement stack
coolant pump.
2.
H
Remove the ground wire (I) from the bracket.
I
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3.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Remove the pump bracket (J).
NOTICE
Do not discard the pump bracket.
The pump bracket will be installed
onto the replacement stack coolant
pump.
J
4.
Remove the rubber bushing (K).
K
TSB #: 21-01-045H-1
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STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
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5.
Attach the rubber bushing to the new stack
coolant pump.
The rubber bushing and stack coolant pump
housing are indexed with a land and groove.
Align the groove in the rubber bushing with
the land on the stack coolant pump housing.
6.
Attach the pump bracket and hose from the
original stack coolant pump to the new stack
coolant pump.
7.
Install the replacement stack coolant pump
to the vehicle.
8.
Reinstall all removed parts in reverse order
of removal.
NOTICE
Reprogram the radio presets
recorded from step 3 on page 2.
TSB #: 21-01-045H-1
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9.
STACK COOLANT PUMP REPLACEMENT (SERVICE CAMPAIGN T6A)
Perform air bleeding of stack cooling system.
Refer to the service manual section: Fuel
Cell System > Thermal Management
System > Stack Coolant for proper service
procedure.
10.
To assist with bleeding air from the cooling system; during the air bleed process repeatedly
squeeze the stack coolant hoses by hand at the coolant pump (A) and at the upper radiator
hose (B).
BB
11.
Check and clear any DTC that may have set
during the pump replacement procedure.
12.
The service procedure is now complete.
TSB #: 21-01-045H-1
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