U04AAInvalid Data Received From Hybrid/EV Battery Interface Control Module J
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U04AA flags invalid data from interface module J, the tenth slot. From here on the series only matters for packs with ten or more monitored sections; a nine-module ID.4 battery or an eight-board GM pack like the one in table 16OBDG02 has no J at all. GM's Ultium family, by contrast, assembles packs from anywhere between six and 24 modules of one design, per Wikipedia, and the larger ones clearly exceed ten. No manufacturer publishes U04AA or a threshold for it, and none of the indexed service bulletins mentions it. Likely triggers are the same as for the lower letters: a disturbed isolated link, a damaged connector or a faulty board. U01A9 means J is silent, U0343 incompatible software.
- What you may notice
- Battery or EV system warning
- Power or charging rate reduced
- Likely causes
- PossibleDisturbed isolated data link inside the pack
- PossibleDamaged connector at module J
- PossibleInterface control module J faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.