October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.
TWC Protection
Scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the
PCM has detected conditions appropriate to operate in Three-Way Catalytic Converter
(TWC) Protection mode. This is determined based on the engine load and the engine coolant temperature. While in TWC Protection, the PCM will decrease the air-to-fuel to a value that depends on mass air flow. Higher mass air flow equals a lower air-to-fuel ratio.