Diagnostic article Generic OBD-II
P2247: The bank 2 upstream sensor reference-line continuity diagnosis
Understand P2247’s warmup and normal-operation paths and why internal sensor electronics state matters.
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.
P2247 is the generic reference-voltage circuit/open code for bank 2 sensor 1. GM's wideband-sensor implementation identifies an open-load diagnosis at the RE line and uses several checks inside the sensor interface electronics.
Different interface modes provide different evidence
One path examines stored continuity-test information around an aborted interface RAM check in warmup mode. Another normal-mode path uses the Nernst-cell current condition. A further path observes electrically corrected Nernst voltage while pump-current operation is active.
These are not interchangeable with a simple disconnected-sensor resistance reading. The applicable interface mode determines which observation is available and what a missing or abnormal result means.
A ready sensor is part of the test conditions
The source includes a heated-sensor qualification, expressed as ceramic temperature above 790 °C or completion of the heating-up phase, along with power and inhibition conditions. The temperature is an internal readiness criterion, not a temperature a technician should try to reproduce by externally heating the sensor.
Useful diagnostic information includes interface mode, continuity-result availability, reference-line status and sensor readiness. An unsuccessful check while the interface is idle or unready is not necessarily the same event as the documented open-load diagnosis.
The summary describes internal signal-line behavior but supplies no universal connector mapping. It does not isolate wiring, the sensor element or interface electronics as the failed part. Use the exact vehicle procedure to distinguish those causes before selecting a repair.
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 294 · GM PDF, physical page 295 · GM PDF, physical page 296.
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 Reference Voltage 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