U0346Software Incompatibility With Hybrid/EV Battery Interface Control Module M
- Generic OBD-II code · Network
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- With M the row passes the common twelve-board size. GM's 2018 hybrid table 18OBDG02 includes lost-contact codes for interface modules up to M (U01AC) in its bundle BICM Loss of Comm and adds that GM shares software across programs, so a code counts only where the program in question uses it. A matching bundle for software codes such as U0346 is not listed. The one GM pack plainly beyond twelve modules is the Hummer EV, whose Ultium battery Wikipedia describes as two layers of twelve modules each, wired in parallel at 400 V. How GM addresses the monitoring units in that pack is not published, so no vehicle is known to set U0346. U04AD is M's invalid-data code.
- What you may notice
- Battery or propulsion warning
- Power or charging limited
- Code seen only on very large packs
- Likely causes
- LikelyThirteenth board on a software level the controller rejects
- PossibleController software variant for another pack configuration
- RareBoard installed in the wrong layer or position of a multi-layer pack
- Inspection (ITP)
- Can matter for the ITP: it concerns the emissions system.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.