P0B84Hybrid/EV Battery Voltage Sense O Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B84 is stored when channel O sits above the upper limit of a credible cell voltage. For GM lithium-ion packs that limit is 4.8 V, held 1.4 s in a 2 s window, Type A; the 2016 program with a separate sense module tolerates up to 4.90 V and counts 14 failures in 18 samples, also Type A. GM's BAS Plus mild hybrid uses a lower ceiling of 4.65 V and a Type B rating. On the 2012 two-mode hybrids the reading belongs to NiMH block 15, which must exceed 23 V in 15 of 20 samples. For the driver the effect is a warning and a battery that is no longer charged fully or used for electric drive. Since true overvoltage is rare, the measuring lead and the input of the monitoring electronics are checked first.
- What you may notice
- MIL and battery warning
- Charging ends early
- Less electric assist
- Likely causes
- LikelySense lead O shorted to a higher cell tap
- PossibleMonitoring input of channel O reading too high
- RareCell overcharged because balancing failed
- 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.