OBD-II code · Powertrain (generic, extended)
P2096 Post Catalyst Fuel Trim System Too Lean (Bank 1)
Long-term fuel trim derived from the downstream oxygen sensor on bank 1 has reached the lean limit. The downstream-trim correction is a fine adjustment that runs after the main trim from the upstream sensor; persistent excursion suggests a degraded catalyst, an exhaust leak after the catalyst, or a drifting downstream sensor.
Is it safe to drive with P2096?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyExhaust leak after catalyst (post-cat sensor sees ambient air)
- PossibleDownstream sensor drifting
- Less likelyCatalyst lightly degraded
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, Exhaust Pipe Post Cat
Related codes
- P2098Post Catalyst Fuel Trim System Too Lean (Bank 2)
- P2093A Camshaft Position Actuator Control Circuit High (Bank 2)
- P2094B Camshaft Position Actuator Control Circuit Low (Bank 2)
- P2095B Camshaft Position Actuator Control Circuit High (Bank 2)
- P2097Post Catalyst Fuel Trim System Too Rich (Bank 1)
- P2099Post Catalyst Fuel Trim System Too Rich (Bank 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.