U01A6Lost Communication With Hybrid/EV Battery Interface Control Module G
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U01A6 means battery interface control module G no longer reports to the battery controller. Because these boards sit inside the high-voltage pack, the chain runs between modules whose ground levels differ by hundreds of volts, so the link has to be galvanically isolated; Wikipedia's battery management article names optical couplers and radio as the hardware routes. Diagnosis therefore starts on a de-energised pack: note which neighbouring letters still report, then look at G's plugs for corrosion, coolant or moisture and carry out an insulation test before swapping parts. GM's 2016-2019 plug-in tables classify G as Type A, lighting the MIL in the first failing trip, and Audi's bulletins for the 2016 A3 e-tron and the Q5 e list U01A600 together with the other seven letters.
- What you may notice
- MIL and battery warning lamp
- Insulation fault code stored alongside if moisture has entered
- Reduced power or no ready mode
- Likely causes
- LikelyChain link between module F and module G interrupted
- PossibleMoisture or coolant at the chain connectors of module G
- PossibleIsolating coupler (transformer, optocoupler) on the link to G failed
- RareBattery interface control module G 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: €150 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.