Answer :
Final answer:
Technician A is correct because the PCM controls the canister purge in the EVAP system. Technician B is incorrect because the EVAP system is for preventing fuel vapor emissions, not for controlling CO emissions from the engine.
Explanation:
The question involves determining who is correct between Technician A, who says the PCM controls the amount of canister purge based on other inputs, and Technician B, who says the EVAP system controls the amount of CO emissions produced by the engine. Technician A is correct because the Powertrain Control Module (PCM) indeed controls the purging of the canister in the Evaporative Emission Control System (EVAP), which is based on various inputs such as engine speed, temperature, load, etc. Technician B is incorrect because the EVAP system is designed to prevent gasoline vapors from the fuel system from escaping into the atmosphere, not to control carbon monoxide (CO) emissions produced by the engine. Modern automobile engines use computerized controls along with exhaust catalysts to manage CO and other emissions, following the reaction: 2 CO + O2 → 2 CO2.
Thus, the correct answer is (option A) Technician A.
