2021 Hyundai Elantra ICU Software Update for Warning Lights

Hyundai has released Service Campaign 21-01-056H to address a software issue with the Integrated Central Control Unit (ICU) in certain 2021 Hyundai Elantra (CN7) vehicles. This Hyundai Elantra ICU update aims to fix various symptoms that owners might experience.

Important Warnings for Owners

Hyundai mandates that dealers must perform this Service Campaign on all affected vehicles prior to customer retail delivery. Additionally, the update must be completed whenever an affected vehicle is in the shop for any maintenance or repair. This ensures that all eligible vehicles receive the necessary software update promptly.

Symptoms

Owners of affected 2021 Hyundai Elantra vehicles may notice several concerning symptoms related to the ICU software issue. These can include:

• Multiple warning lights displayed on the instrument cluster.
• A noticeable reduction in power steering assist, making the steering feel heavier or less responsive.
• Difficulty or inability to shift the vehicle out of Park.

Fault Codes / DTCs

When these symptoms occur, technicians may find specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's system. These codes help pinpoint the nature of the electronic communication issues:

Code	Description	Module
C181287	CAN Time-out Gateway	ICU
C181208	CAN Time-out Gateway	ICU
C180581	LKAS CAN Signal Error	ICU
C181887	CAN Time-out BCA	ICU
B109052	TCU Missing Error	TCU

Diagnosis and Trigger Conditions

To diagnose the issue, a technician will check the current software version (ROM ID) of the ICU. If the ROM ID is an older version (1.05), it indicates the vehicle is affected and requires the Hyundai Elantra ICU update. The update will bring the ROM ID to version 1.06.

Repair Procedure Summary

The repair involves updating the software of the Integrated Central Control Unit (ICU) using the Hyundai Global Diagnostic System (GDS). The general steps for this Hyundai Elantra ICU update are:

1. Check Software Version: The technician will first verify the current ICU ROM ID against the information table provided in the bulletin.
2. GDS Update in Auto Mode: The GDS ICU update should initially be performed in Auto Mode. For detailed procedures on using the tablet-based Mobile GDS ECU update, technicians are directed to refer to TSB 15-GI-001.
3. Manual Mode Recovery: If the ICU update begins but then fails in Auto Mode, the technician will switch to Manual Mode to complete the update process. The manual mode password for the CN7 ICU 91950/91951-AAXXX is 5051.
4. DTC Clearance: After the software update is successfully completed, the technician will check all system menus for any Diagnostic Trouble Codes and erase them.
5. Confirmation: Finally, the technician will confirm that the vehicle is operating normally and that all symptoms have been resolved.

Required Parts or Software

This service campaign primarily involves a software update. The relevant ICU part numbers and their corresponding ROM IDs are:

• ICU Part Numbers: 91950-AA010 to 91950-AA990 and 91951-AA010 to 91951-AA590.
• Old ROM ID: 1.05
• New ROM ID: 1.06

Owner Action

If your 2021 Hyundai Elantra is experiencing any of the described symptoms, such as multiple warning lights, reduced power steering, or difficulty shifting out of Park, you should contact your authorized Hyundai dealer. Since this is a service campaign, the software update will be performed free of charge. The estimated operation time for the update is 0.3 hours.

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Source: NHTSA ID 10200074