OBD-II code family
Post-Catalyst Fuel Trim Faults (4 codes)
4 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
What these codes mean
These four entries distinguish post-catalyst fuel-trim results by bank and direction. P2096 is too lean on Bank 1 and P2097 too rich on Bank 1. P2098 and P2099 preserve the corresponding lean and rich results on Bank 2. Keep the exact report when choosing the diagnostic branch; these are not four names for a failed oxygen sensor or catalytic converter.
The controller assesses a defined fuel-control or feedback result. Audi’s cited CEUA/CGTA table uses a second lambda-control-loop criterion, while Ford’s covered 2024–2025 UEGO FAOS monitor lists its own sensor and system prerequisites. The label does not certify a healthy upstream mixture, identify a particular exhaust leak or establish a universal rear-sensor voltage or fuel-trim limit.
A software example also requires its exact application. Volkswagen bulletin 01-21-05 covers particular 2020–2021 Atlas and Atlas Cross Sport 3.6L CDVC software rows for erroneous P2096–P2099 reports. Other rows in the wider model table concern P060C alone. A shop must match the actual vehicle and software rather than applying a generic software-first or replacement-first rule.
For the listed Bank 1 applications, Subaru bulletin 18-228-25 revises rear-oxygen-sensor diagnosis with prescribed response checks in place of older fixed-voltage judgments. Its non-PHEV branches and 2019–2023 Crosstrek Hybrid insertion are distinct. This is professional procedure context, not a generic owner fueling, engine-speed or sensor-swap test and not direct evidence for Bank 2 procedures.
Identify the actual bank, exhaust and sensor arrangement. Save companion mixture, misfire, pressure, sensor and catalyst faults before clearing. Have the matched response, exhaust-integrity, air/fuel and relevant electrical checks performed. One static reading, normal-looking long-term trim or disappearance after a trial sensor replacement does not establish the cause.
Exhaust work and induced operating tests need the specified cooling, support, ventilation and equipment. Do not go beneath a hot vehicle to compare catalyst temperatures or swap sensors as a generic test. Follow actual warnings and arrange assessment for severe rough running, loss of response or exhaust fumes. Quote the demonstrated repair rather than assigning a price by bank or code.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.