P0BA1Hybrid/EV Battery Voltage Sense U Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0BA1 is stored when sense U reads close to zero. GM's lithium-ion controllers of the 2016 Volt and ELR and of 2019 treat 0.2 V or less over 1.4 s in a 2 s window as a Type A fault, provided no open sense line, lost slave communication or balancing fault is already active. The 16OBDG02 programme with its own battery sensor module uses under 0.20 V in 14 of 18 samples. GM's eAssist mild hybrid applies a much higher limit of 1.4 V in 7 of 10 samples, Type B. The two-mode NiMH trucks have no channel U. A short in the sense lead or a failed measuring input is the most likely finding.
- What you may notice
- MIL and EV or hybrid system warning
- Propulsion power limited
- Likely causes
- LikelySense lead U shorted towards ground or a lower cell
- PossibleDead measuring input for channel U
- RareCell U internally shorted or deeply discharged
- 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 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.