DME 7.8 DME 7.8 0 · 0-78.1P0491

DME 7.8 DME 7.8 0 0-78.1P0491 Secondary Air Injection System, Bank 1 – Below Limit Diagnosis conditions • Intake air temperature 4.5 - 60 °C • Engine temperature 4.5 - 102 °C • Mass air flow 36 - 150 kg/h • Engine starting temperature less than 42 °C • Altitude correction factor greater than 0.75 • Oxygen sensors 1 and 2 ahead of TWC are ready for operation • The secondary air injection pump is switched on • Diagnosis has not yet taken place during this cycle Possible fault cause ♦Secondary air injection pump is not triggered ♦Secondary air injection pump does not work ♦Air supply lines restricted ♦Electric change-over valve does not function ♦Air change-over valve does not function ♦Vacuum system leaking Affected terminals III/11 and III/14 2665 P0491 0-78.1 page 1 Printed in Germany – 6, 2002 p0491