U01ADLost Communication With Hybrid/EV Battery Interface Control Module N
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U01AD names battery interface control module N, the fourteenth board in a monitoring chain. No manufacturer documents this code publicly, and even GM's broad fault bundle stops at M. The reason such codes exist at all lies in CARB's rule 1968.2, section (e)(15.2.3): hybrid OBD systems must supervise the electronic inputs of the energy storage system, such as cell voltage and temperature sensing, and store separate codes that pinpoint the smallest unit replaceable in service. A pack built from many separately replaceable monitoring boards thus needs one code per board. In a daisy chain of the kind GM describes, a stored U01AD would mean that the boards up to M still answer and N is the first one lost. Neighbouring codes for N are U04AE and U0347.
- What you may notice
- Battery warning, power and charging limited
- Cell data of one pack section missing in the scan tool
- Likely causes
- LikelyChain connection between module M and module N interrupted
- PossibleBattery interface control module N 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.