Air pump system
Air pump system (B5202S, B5252S certain markets)
When the engine is being started from cold, an electrical air pump
which draws air to the exhaust channels is activated. This starts an
afterburning process which means smaller hydrocarbon and carbon
monoxide (HC and CO) emissions and reduces the catalytic converted
warm-up period.
The pump starts when the car has been started and is moving. It stays
working until the catalytic converter has reached normal working
temperature.
The pump whines softly, this is normal.
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