U01AFLost Communication With Hybrid/EV Battery Interface Control Module P
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U01AF closes the row and stands for battery interface control module P, the sixteenth monitoring board; no manufacturer documents it publicly. Some packs exceed that count: according to Wikipedia the Hummer EV battery consists of 24 Ultium modules, although that platform monitors wirelessly and GM does not publish how it maps modules to codes. The code is easily mixed up with its neighbours. U0111, U0112, U014A and U014C mean that a battery energy control module itself has vanished from the vehicle network, and U019B points to the on-board charger. U01AF, by contrast, describes a sub-board inside the pack that only the battery controller can see, so that controller must itself be awake and reachable to log it.
- What you may notice
- Battery warning while the battery controller itself still communicates
- Power limited, charging blocked
- Likely causes
- LikelyInternal link to module P interrupted
- PossibleBattery interface control module P defective
- 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: €100 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.