P0BABHybrid/EV Battery Voltage Sense W 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
- A W channel reading at or near zero sets P0BAB. How low is too low depends on the battery: GM's lithium-ion modules of 2016 and 2019 react to 0.2 V or less held for 1.4 s within a 2 s window, Type A, and the 16OBDG02 programme to under 0.20 V in 14 of 18 samples at 100 ms. The eAssist mild hybrid already fails below 1.4 V, seven of ten samples, as long as the 12 V supply exceeds 8.8 V and P1B38 is not active; that fault is Type B. All of these tests stand down while an open sense line fault is present, so a simply broken lead shows up as P0BA9. P0BAB on its own suggests a short towards a lower potential, a dead measuring input or a deeply discharged cell. Power and charging are usually restricted.
- What you may notice
- Hybrid or EV warning and MIL
- Reduced power output
- Charging limited or blocked
- Likely causes
- LikelySense lead W shorted to a lower cell potential
- PossibleMeasuring input for W on the monitoring board failed
- RareCell W deeply discharged or internally shorted
- 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.