P0B9FHybrid/EV Battery Voltage Sense U Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B9F covers an open or high-resistance sense U lead, channel twenty-one. From U onward the 2012 two-mode trucks drop out, as their pack has only twenty blocks, so this code is a lithium-ion matter at GM. In the eAssist mild hybrid the test is the familiar one, lines N and N-1 both under 1.4 V with a change above 0.5 V within 200 ms in 7 of 10 samples, Type B, but it is now blocked by P1B38 instead of P1B37. The 16OBDG02 programme measures the sense line resistance and sets above 30.00 in 7 of 9 samples, Type A. The 2016 Volt and ELR decide in 0.6 s, the 2019 controller in 0.8 s of 1.6 s, both on adjacent-cell differences of 1.3 V and splice checks.
- What you may notice
- MIL and hybrid or EV system warning
- No start or ready mode on some vehicles
- Charging not possible
- Likely causes
- LikelySense lead U interrupted or detached from its cell
- PossibleCorroded terminal raising the resistance of lead U
- RareFault in the balancing circuit used for the channel U test
- 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 – €6,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.