U01A0Lost Communication With Hybrid/EV Battery Interface Control Module A
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U01A0 names battery interface control module A, the first slave board that reports cell voltages and temperatures of its pack section to the battery controller. GM's 2016-2019 plug-in hybrid tables explain how the code arises: the battery system module talks to eight such boards over a UART daisy chain; once U179C shows that data has stopped, it switches the boards into an internal loopback test and stores the code of the first board it still cannot reach, in 2016 after 5 s above 10.2 V, Type A with MIL on the first trip. Because A sits next to the master, a break ahead of A silences every board in the chain while only A gets named. Audi lists U01A000 for the 2016 A3 Sportback e-tron, which then refuses to make the drive system ready.
- What you may notice
- Vehicle does not become ready to drive, red hybrid/EV warning
- MIL on after the first failing trip (GM Type A)
- Further module codes or U179C stored at the same time
- Likely causes
- LikelyChain wiring or connector between battery controller and module A interrupted
- PossibleModule A without supply from its cell group or low-voltage feed
- PossibleBattery interface control module A defective
- RareChain interface of the battery controller itself 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: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.