| The secondary air system blows air in behind the exhaust valve for max. 65 seconds after a cold start (+15 °C ... +35 °C coolant temperature). This produces an oxygen-rich exhaust gas, causing afterburning and reducing the heat-up phase of the catalytic converter. The Motronic control unit -J220- activates the secondary air inlet valve -N112- (change-over valve) and combination valve via the secondary air pump relay -J299-. Additionally, after each subsequent engine start (up to max. 85 °C engine temperature), the secondary air system will, after a 20-second delay, switch in for 5 seconds during idling and will be checked by the self-diagnosis. |
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