P0B42Hybrid/EV Battery Voltage Sense B 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
- P0B42 sets when cell voltage channel B reads implausibly low, below what any usable cell would show. GM's battery energy control module sets it at 0.2 V or less for 1.4 s within a 2 s window, Type A, one trip, and only when no open sense line, slave communication or balancing fault is present. FCA uses P0B42 as Voltage Sense 2 Circuit Low on the 2022 Grand Wagoneer and Wagoneer with the 5.7 L eTorque mild hybrid; its bulletin calls the MIL false, mentions inoperative start-stop and a car that seems to run on fuel only, and prescribes a battery pack control module update. Cells that are actually weak set separate cell voltage codes. High and range faults are P0B43 and P0B41.
- What you may notice
- MIL on
- Start-stop inoperative
- Vehicle behaves as if running on the engine only
- Likely causes
- LikelyBattery pack control module software causing a false MIL (FCA eTorque)
- PossibleSense line shorted to the adjacent line or to the cell negative
- RareMeasurement input of the cell monitoring chip 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: €50 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.