Warm Up Catalyst Efficiency Below Threshold (Bank 2)
The pre-cat (warm-up) catalyst on bank 2 has lost too much oxygen storage capacity. Its primary purpose — quickly reaching light-off after a cold start — is no longer met within the OBD limits.
Affected components
- Warm up catalyst
- Oxygen sensor upstream
- Oxygen sensor downstream
Common causes
- High likelihood: Pre-catalyst aged or damaged
- Medium likelihood: Oxygen sensor drift
Possible symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.