Electric Secondary AIR System: Notes
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The electric secondary AIR system consists of an electric AIR pump, single or dual combination check air injection diverter (AIR diverter) valve(s), an AIR bypass solenoid, an AIR relay, a powertrain control module (PCM) and connecting wires, and vacuum hoses.
- The PCM requires cylinder head temperature (CHT), intake air temperature (IAT), and crankshaft position (CKP) inputs to initiate the secondary air injection function.
- When the engine is started, the strategy will determine when to enable the electric AIR pump. The PCM signals the AIR relay and the AIR bypass solenoid, after a (5 to 15) second delay, to begin system operation. Once the catalyst is lit-off, the PCM then signals the AIR relay to stop AIR pump operation and to close the AIR bypass solenoid from supplying vacuum to the AIR diverter valve(s).
- The AIR relay provides the start-up signal and will switch the high current required to operate the AIR pump.
- The AIR bypass solenoid applies a vacuum to the AIR diverter valve(s) causing it to open and to allow air to flow into the exhaust manifolds.
- The function of the water shield, (if equipped), is to provide the AIR pump with a source of dry air.
- The electric AIR pump delivers the required amount of air to control emissions during engine operation. Air is forced into the exhaust manifolds to oxidize the hydrocarbons and carbon monoxide created by running rich at start up.