P2BA4
Catalyst Feedgas Performance
The ECM detects that the exhaust gas composition reaching the catalyst (feedgas) deviates from the calibrated profile. Pre-cat O2 measurement and air-fuel control are inconsistent with engine operation.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Common causes
Ordered by how often each turns out to be the cause.
- Long-term fuel trim drifted out of nominal rangeCommon
- Exhaust leak upstream of catalystPossible
Parts involved
- Catalytic Converter
- O2 Sensor Pre Cat
- ECM
P2BA4 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.