Diagnostic article Generic OBD-II
P2240: A positive-current circuit code with more than one wideband-sensor path
Learn how P2240 uses internal continuity comparisons and why the source also lists prolonged protection activity.
Read before applying this article
Documented application
2025 GM 25OBDG07A Part 2 monitor tables only; model, engine and transmission applicability are not established by the unresolved application-matrix filename join.
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.
P2240 is the generic positive-current control circuit/open diagnosis for bank 2 sensor 1. The GM source describes an open circuit at the wideband interface's Apes line and compares internal continuity measurements of the pump and Nernst cells.
The continuity test compares internal responses
In the warmup-mode path, the interface applies its internal reference current to different sensor lines and compares voltage drops against a baseline with the lines open. The thresholds depend on reference-current amplitude and the documented sensitivity factor, rather than one universal external resistance value.
Stored test information can also be used when the interface operation is aborted. Consequently, the absence of a currently visible test pulse does not establish that no continuity evidence contributed to the code.
An additional path changes the interpretation
The source assigns P2240 to prolonged activation of its blackening-protection function as well. This means the generic “open” label does not identify a broken conductor in every documented path. Determining which diagnostic status actually failed is essential before choosing a circuit test.
Sensor temperature, mode and operating readiness qualify these checks. The source does not provide a connector pinout or establish that a static resistance measurement reproduces the internal sequence. Preserve interface status, the available continuity results and protection activity with the code. The monitor narrows the electrical investigation but cannot independently identify wiring, sensor or control electronics as the component requiring replacement.
Source and scope
2025 GM 25OBDG07A Part 2 monitor tables only; model, engine and transmission applicability are not established by the unresolved application-matrix filename join. These are documented monitor criteria, not a universal repair procedure. GM PDF, physical page 312 · GM PDF, physical page 313 · GM PDF, physical page 314 · GM PDF, physical page 315.
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
O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1
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