OBD-II code · Powertrain (generic, extended)

P2097 Post Catalyst Fuel Trim System Too Rich (Bank 1)

Long-term post-catalyst fuel trim on bank 1 has reached its rich limit. The downstream sensor sees more reductant than expected, often pointing to a degraded catalyst that no longer stores oxygen, or a failing downstream sensor biased rich.

Is it safe to drive with P2097?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyCatalyst oxygen storage exhausted
  • PossibleDownstream sensor biased rich

Symptoms

  • Check engine light on
  • Failed emissions inspection
  • Possibly slightly increased fuel consumption
  • Sulfur (rotten egg) smell from exhaust under load

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.5–4 h
Emissions test
Likely to fail
After the fix
A drive cycle is needed before the light stays off
Parts involved
Oxygen Sensor Downstream, Catalytic Converter

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.