23-EE-004H

GROUP
ENGINE
ELECTRICAL
SYSTEMS
Technical Service Bulletin
SUBJECT:
DATE
MARCH, 2023
NUMBER
23-EE-004H
MODEL(S)
SANTA FE PLUG-IN
HYBRID
(TM PHEV)
HCU UPGRADE – G2T-GDI OIL DILUTION IMPROVEMENT
DESCRIPTION: This bulletin provides information related to the Hybrid Control Unit (HCU) software
update for Santa Fe Plug-in Hybrid (TM PHEV) vehicles to improve the following symptom:
1. Oil Dilution: Some vehicles may experience increased oil consumption and white smoke due to
the diluting of engine oil with fuel because of the frequent transition between EV ↔ Engine
mode during the winter season
a. Modify fuel injection strategy below 10℃ and add oil heating function based on the
driving pattern.
APPLICABLE VEHICLES: All 21-23MY Santa Fe Plug-in Hybrid (TM PHEV) equipped with 1.6L
Gamma II turbocharged engines
GDS INFORMATION: System Selection: HCU/LDC:
Event #
Description
#929
TM PE PHEV 1.6T-GDI OIL DILUTION IMPROVEMENT [HCU]
WARRANTY INFORMATION:
Model
Op Code
Operation
Op Time
Causal Part
Nature
Code
Cause
Code
Santa Fe Plug-in
Hybrid
(TM PHEV)
36600F12
HCU
UPGRADE
0.5 M/H
36600-3DBH5
I14
ZZ3
NOTE 1: Normal Warranty Applies
Circulate To: Service Manager, Warranty Manager, Service Advisors, Technicians, Fleet Repair
SUBJECT:
HCU UPGRADE – G2T-GDI OIL DILUTION IMPROVEMENT
SERVICE PROCEDURE:
NOTICE
To verify the vehicle is affected, be sure to check the version of the vehicle’s HCU
ROM ID with reference to the HCU ROM ID TABLE below before attempting to upgrade
the control unit software.
You must attach a 12V battery charger to the vehicle before performing GDS HCU
Update. This is to prevent a battery saver condition from occurring since Santa Fe
Plug-in Hybrid use a smaller battery.
You must initially perform GDS HCU Update in Auto Mode.
• If the HCU Update starts but then fails in Auto Mode, disconnect the battery cables and
touch the cables together for one minute. Reconnect the battery cables, attach the battery
charger and perform the update in Manual Mode to recover.
• Refer to the General Instructions found in TSB 15-GI-001 (GDS Mobile).
1. After the HCU Update is completed, check for Diagnostic Trouble Codes and erase
any DTC.
HCU ROM ID TABLE:
Event
Model
Part Number
Santa Fe Plug-in
Hybrid
(TM PHEV)
#929
(HCU)
391312MNC0
Old
ROM ID
GTMC2N6PNS1-C940
New
GTMC2N6PNS2-C940
MANUAL UPDATE: If the HCU Update starts but then fails in Auto Mode, perform the
update in Manual Mode to recover.
Model
Event
Menu
Santa Fe
Plug-in Hybrid #929 (HCU) TM PE PHEV 1.6T-GDI 4WD 19inch 36600-3DBH5
(TM PHEV)
TSB #: 23-EE-004H
Password
3575
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