(F) Catalyst Monitor Outputs

The catalyst monitor diagnostic is sensitive to the following conditions:
- Exhaust leaks
- HO2S contamination
- Alternate fuels

Exhaust system leaks may cause the following:
- Preventing a degraded catalyst from failing the diagnostic.
- Causing a false failure for a normally functioning catalyst.
- Preventing the diagnostic from running.

Some of the contaminants that may be encountered are phosphorus, lead, silica, and sulfur. The presence of these contaminants will prevent the TWC diagnostic from functioning properly.