Volkswagen Workshop Service and Repair Manuals

The secondary air system blows air in behind the exhaust valve for 65 seconds during the cold start (+15 °C ... +35 °C coolant temperature). This produces an oxygen rich exhaust gas, causes afterburning and reduces the heating-up phase of the catalyst. Activation occurs from the Motronic control unit (J220) via the secondary air pump relay (J229) to secondary air inlet valve (N112, change-over valve) and combi-valve. 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.

Note:

For vehicles 05.00 ▸ the secondary air inlet valve (N112) and also the activation of the combi-valve via vacuum has been deleted. If, on these vehicles, the secondary air pump runs the combi-valve will open at a positive pressure of approx. 60 ... 70 mbar.