Diagnostic article Generic OBD-II
P0B43: Block-two high voltage is evaluated without the paired low condition
Read the GM P0B43 single-channel high-limit test and distinguish it from P0B42’s two-block rule.
Read before applying this article
Documented application
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P0B43 monitors a block-two voltage indication above 23V in this GM implementation. Its high-limit row evaluates block two directly. That differs from the neighboring P0B42 low-limit row, which requires both block two and block three to be low.
Do not import the opposite fault’s logic
A high block-three reading is not listed as a prerequisite for P0B43. The qualifying conditions are controller run mode, suitable low-voltage supply and no P0A1F controller-performance fault. Failure is counted through 15 qualifying samples out of 20 at 100ms intervals.
The code therefore reports a specific channel's upper signal limit. It does not establish that the whole battery was overcharged or that another block must share the same indication.
Preserve the channel rather than only a maximum
Save block-two voltage and its identity, the independent pack reading and any rationality or neighboring-channel faults. A “maximum block voltage” display without the channel number can lose the evidence needed to follow the correct diagnostic branch.
The document does not identify the physical block position, sensing-wire arrangement or required replacement. Those are vehicle-specific service questions. A trained battery technician must use the applicable diagram and approved tests, with high-voltage isolation before access. Do not deliberately raise battery voltage to reproduce the code or rely on a scanner to verify electrical safety.
Keep historical and current fault status distinct in that record.
Source and applicability
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established. GM PDF, page 223.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Hybrid/EV Battery Voltage Sense B Circuit High
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT