Diagnostic article Generic OBD-II
P0D23: Unexpected charger-bus current during precharge
P0D23 detects charger-bus current above 0.35 amp in a specific GM precharge state with heating and cooling inactive.
Read before applying this article
Documented application
15OBDG01 Hybrid Diagnostics, cited controller and monitor only. Historical calibration limits are not universal specifications; per-code vehicle, engine and hardware applicability must be verified.
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.
Why a small current matters here
P0D23 is labeled charger output shorted in GM’s table, but the detection condition is more specific than a general high-current warning. Charger-bus current must exceed 0.35 amp while the multipurpose contactor is open and the charger contactor is in its precharge state. System voltage must exceed 9 volts.
The monitor also requires no active heating or cooling and no listed faults affecting the high-voltage output-current signal. These exclusions explain why a current value that might be expected in another operating mode can be suspicious during this particular sequence. The threshold is not a maximum allowable current for normal battery charging.
Separate the measurement from the diagnosis
The controller requires four failing observations among five samples taken at 100-millisecond intervals. Its passing period is 0.5 second. A technician should preserve the precharge state, bus-current value and thermal operating mode together; a later normal charging reading does not recreate the conditions that produced the code.
Current-signal fault exclusions are equally significant. If related sensor or communication faults are present, investigate their effect on the current evidence using the applicable service procedure. A reported current is not automatically an independently verified current flow.
The monitor supports an unexpected-current conclusion under constrained conditions. It does not establish the physical location of a short, prove a particular contactor is welded or justify replacement of the charger without further evidence. Precharge involves the high-voltage system, so the table must not be used as instructions for bridging contactors or conducting energized output tests.
Source and applicability
15OBDG01 Hybrid Diagnostics, cited controller and monitor only. Historical calibration limits are not universal specifications; per-code vehicle, engine and hardware applicability must be verified.
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
Battery Charger A Output Shorted
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