Diagnostic article Generic OBD-II
P2239: pump-circuit diagnosis follows a qualified control-factor change
The GM P2239 example evaluates a change in lambda control factor with the upstream sensor near its specified center voltage and control states qualified.
Read before applying this article
Documented application
GM 2009 09OBDG04 Engine Diagnostics, cited bank-one air/fuel pump-circuit control-factor response monitor only. Document-level evidence does not establish per-code vehicle, engine or wiring applicability.
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.
P2239 is associated with the bank-one air/fuel sensor pumping-current circuit in this GM example. Although the generic label describes a high current-control circuit condition, this row evaluates the control system's response rather than providing a simple external high-voltage test.
The reference point is when enabling conditions are met
The monitored change is the absolute lambda control-factor movement from the point at which the secondary conditions become satisfied. The printed boundary is greater than 0.025 lambda. The sensor voltage must be within the narrow 1.49–1.51 V region described by the continuation.
The heater and warm-up states must be ready, closed-loop control active and electrical trimming inactive. The source also requires a qualified forced trim amplitude and stable related control states. Those details explain why an arbitrary change in fuel correction is not equivalent to this diagnostic event.
Keep the controlled response with the signal
Record the relevant sensor value, control-factor baseline and operating-state information. A later voltage reading without the point of comparison cannot demonstrate the change the monitor evaluated. A generic sensor-heater test also does not substitute for this pumping-circuit response assessment.
The table does not identify a failed connector, sensor element or control module, and it supplies no replacement instruction. The exact vehicle diagnostic procedure must establish the cause and verify the controlled response. Do not improvise forced fuel adjustments or energized sensor probing from this parameter summary; the appropriate professional procedure controls those tests.
Source and applicability
GM 2009 09OBDG04 Engine Diagnostics, cited bank-one air/fuel pump-circuit control-factor response monitor only. Document-level evidence does not establish per-code vehicle, engine or wiring applicability.
General Motors source, physical page 9 · General Motors source, physical page 10
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 High Bank 1 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