P2195: A bank 1 lean-biased oxygen-sensor diagnosis based on learned offset

P2195 is generically described as bank 1 sensor 1 biased or stuck lean. The GM implementation shown here evaluates the plausibility of the upstream exhaust-gas sensor through its learned lambda offset. It does not simply require a conventional oxygen-sensor voltage to stay low.

The offset needs qualified confirmation

The listed boundary is a lambda offset greater than 0.07. The row also requires an offset-adaptation debounce condition and describes a slow-adaptation branch. Its 0.1-second evaluation period is therefore not the total time needed to establish the offset or complete the diagnostic.

The continuation requires usable upstream sensor operation and qualified lambda control. Fuel cutoff must not be active in the illustrated branch, and there are conditions governing the return to control afterward. Data collected in a different state may not represent the same check.

What the lean label does not isolate

The offset is a control quantity, not raw voltage or a standard fuel-trim percentage. Confirm that a scan parameter represents the same quantity before comparing its number with 0.07.

A code alone cannot distinguish an actual mixture problem from sensing or control-related causes of the implausible offset. Preserve the bank 1 sensor status, learned offset and adaptation eligibility. Replacing the sensor solely because its name appears in the title skips that distinction. A valid verification needs the sensor and control functions to become eligible and the monitor to complete, rather than just a cleared code or a temporarily plausible display.

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 395 · GM PDF, physical page 396.