P2197: The bank 2 lean-biased sensor check uses an adapted lambda quantity

P2197 is the bank 2 sensor 1 biased/stuck-lean code. The GM table describes an upstream sensor plausibility check based on a learned lambda offset rather than a direct statement that a wire voltage is continuously low.

The learned offset must cross its limit under control

The specified main boundary is above 0.07 for bank 2's offset. The row requires confirmation through offset-adaptation debounce logic. Its continuation includes upstream lambda-control eligibility, sensor readiness and conditions following fuel cutoff.

These qualifications explain why a code can reflect a developed adaptation result rather than a single lean reading. They also explain why a normal-looking sensor value during an ineligible state cannot independently demonstrate recovery.

Use the correct bank and parameter

A bank 1 offset cannot replace the bank 2 quantity used by this monitor. Nor can an ordinary trim percentage or raw sensor voltage be compared directly with the source's lambda-offset threshold without establishing the parameter definition.

Preserve the affected bank's offset, control status and fault sequence. Comparing other bank information under matching conditions can be useful context, but the code itself does not determine whether the cause is local to bank 2 or shared elsewhere in the system.

The summary does not identify a failed oxygen sensor, air path or fuel component. Cause isolation requires the vehicle's diagnostic information. A meaningful retest must allow the relevant adaptation and plausibility monitor to run again; clearing fault memory or observing one plausible value does not reproduce that process.

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 411 · GM PDF, physical page 412.