Code status
Needs verification
Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.
- System
- Fuel / Air
- Scope
- iso-sae-controlled-p0
- Standard
- SAE J2012 / ISO 15031-6
- Source
- legacy-import
Diagnostic boundary
A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.
Do not replace the upstream sensor before checking exhaust leaks and mixture-control faults; the sensor may be reporting a real slow correction.
Useful checks before replacing parts
- Use live data to compare upstream oxygen or air-fuel sensor response during controlled rich and lean changes.
- Check for exhaust leaks ahead of the sensor, wiring faults, contamination, and fuel-control problems that can slow apparent response.
- Review fuel trims and companion heater or circuit codes before blaming sensor age alone.
Related OBD-II codes
These nearby fuel / air entries can help compare wording and fault area. They may share the same verification status as the source database.