Diagnostic article Generic OBD-II
P2629: The upstream bank-two oxygen sensor’s compensation path is open
P2629 checks a calculated compensation-resistance path after the wideband oxygen sensor reaches the required operating state.
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Documented application
2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred.
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.
P2629 concerns the bank-two upstream wideband oxygen sensor’s compensation-resistor path in the cited GM strategy. The controller calculates a parallel resistance between named sensor interface lines and flags a value above 240 ohms as an open-path finding. That is different from diagnosing the air-fuel mixture as lean or rich.
The sensor must be ready for this check
The monitor requires the upstream sensor to be heated. The source accepts either ceramic temperature above 790°C or completion of its heating-up phase. It also requires the requested switch-on mode and a sensor-interface verification history, with no aborted last packet transfer.
Those prerequisites matter: a cold sensor measurement does not directly reproduce this operating-state calculation. The listed fault interval is 0.01 seconds, with two-trip reporting.
Interpret the calculated value carefully
The 240-ohm figure is a controller-calculated parallel path, not a universal instruction to disconnect the sensor and measure every terminal with an ohmmeter. Appropriate service information must define the relevant circuit and permitted test method. Preserve heater readiness, interface mode and the open-path status together. The DTC supports a compensation-circuit concern but does not establish a fuel-trim repair or identify the sensor alone as the proven failed part.
Document scope and source
2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred. These figures explain the cited controller logic, not a vehicle-specific repair instruction. Match the vehicle’s service information before applying them.
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 Pumping Current Trim 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