P0491 Citroen Secondary Air Injection System Insufficient Flow Bank 1
Possible causes
– Secondary air pump with no or low air flow
– Secondary air bypass solenoid leaking /blocked or stuck open /closed
– Secondary AIR air hose restricted
– Secondary air vacuum hoses restricted or leaking
– Secondary air bypass solenoid leaking /blocked or stuck open /closed
– Secondary AIR air hose restricted
– Secondary air vacuum hoses restricted or leaking
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0491 Citroen Description
The secondary air system detected that there was insufficient mass flow change during pump switching (on/off)
Citroen Vehicle:2013 Citroen,2012 Citroen,2011 Citroen,2010 Citroen,2009 Citroen,2008 Citroen,2007 Citroen,2006 Citroen,2005 Citroen,2004 Citroen,2003 Citroen,2002 Citroen,2001 Citroen,2000 Citroen,1999 Citroen,1998 Citroen,1997 Citroen,1996 Citroen,