What are the symptoms of a faulty secondary air pump?

[CoreyRose]

Secondary air pump failure symptoms: First, the malfunction indicator light will illuminate, followed by the appearance of a fault code indicating incorrect secondary air flow; the engine warning light on the instrument panel will turn on, and the engine control unit will record fault code P0411. The working principle of the secondary air pump is: When the engine is running, the crankshaft drive belt drives the air pump to operate, pumping a large volume of low-pressure air flow through a hose into the diverter valve. The function of the secondary air pump is to supply air to the three-way catalytic converter when the engine is cold, utilizing the exhaust gases to react with the oxygen in the air for secondary combustion, thereby raising the temperature of the catalytic converter. This helps the catalytic converter reach optimal operating temperature quickly, reducing harmful emissions and serving an environmental protection purpose.