Hyundai won't release details for 61D004 - defective BMS software
"may have internal cell voltage deviation"
What is likely going on here?
After a month of back-and-forth with Hyundai UK & Hyundai Group there is no real detail. But this is a Safety Recall. There is no concern about the lack of detail by any one.
If you connect "may have internal cell voltage deviation" [as the problem] and "detect potential battery abnormalities" [as the fix] - this update likely addresses cell pack voltage deviation and reading further in the recall this is an issue when being charged. What is unsaid, given no one will talk details is whether this is a CCS / high current issue (likely it is).
This data to know the significant of deviation is already provided by the BMS on the canbus (7E4) 220101. If there is a fix, either the data wasn't used / checked, or the check parameters were incorrect / insufficient.
Hyundai will not admit nor release details.
There is no "confidential intellectual property of Hyundai and its suppliers" - this is a serious safety issue that can be largely mitigated in the first instance by honesty.
It's taken Hyundai 6 years to realise this. Or has it?
The MY22-23 (June 2021 - June 2023) does not have this problem, the architecture of the car hasn't changed so the BMS engineers realised the oversight / mistake (or just didn't make the same mistake again) and released and tested new BMS firmware before June 2021.
Hyundai looks to have taken around 5 years to admit the issue, since it could reasonably have known. In that 5 years it is likely any deviationss in aging packs have got worse and manifested as a serious safety issue.
If the detail update was examined and it's is found to have increased code around cell balancing that would be a pointer at the traction batteries having deteriorated more than they needed to and that Hyundai are worried about a potential warranty claim. Not dissimilar to the previous large scale recall.
Hyundai's final response
I'm including this as it represents the level of discussion that is willing to be had. It's pretty much in line with the worst that could be expected. Close Ranks, admit nothing beyond what is compelled, don't co-operate.
1. Why was this campaign introduced?
The purpose of Campaign 61D004 is to enhance the Battery Management System's capability to detect potential battery abnormalities earlier and more reliably, thereby improving preventive protection measures.
2. What exactly has changed in the software?
The update introduces enhanced monitoring and diagnostic logic within the Battery Management System (BMS).
Key improvements include:
Expanded monitoring coverage during both driving and parked conditions.
Improved sensitivity to battery cell condition changes.
Earlier identification of potential irregularities.
Faster activation of warning and protective functions when required.
3. Which modules are updated?
The software update applies to the vehicle's Battery Management System (BMS), which is responsible for monitoring and managing the high-voltage battery system.
The BMS performs functions such as:
Battery management system
Battery cell voltage monitoring
State of Charge (SOC) & State of Health (SOH)
Fault diagnostics
The purpose of this update is to strengthen the system's ability to identify and respond to potential battery irregularities at an earlier stage.
While we are able to describe the functional improvements, we are not able to provide detailed source code, software architecture, algorithms, calibration parameters, and proprietary engineering data, as they constitute confidential intellectual property of Hyundai and its suppliers.
As such, this email constitutes our final response on this matter.