Need to know whether you have a gas/petrol or diesel engine, and also, if you're in Europe, if you have the diesel engine with the DPF.
The 2005 Volkswagen Passat runs on premium unleaded (recommended).
The 2013 Volkswagen Passat runs on regular unleaded.
The 2012 Volkswagen Passat runs on regular unleaded.
The 2004 Volkswagen Passat runs on premium unleaded (recommended).
The 2008 Volkswagen Passat runs on premium unleaded (required).
The 2002 Volkswagen Passat runs on premium unleaded (recommended).
The 2007 Volkswagen Passat runs on premium unleaded (required).
The 2006 Volkswagen Passat runs on premium unleaded (required).
The 2014 Volkswagen Passat runs on regular unleaded.
The 2003 Volkswagen Passat runs on premium unleaded (recommended).
The 2009 Volkswagen Passat runs on premium unleaded (recommended).
The 2001 Volkswagen Passat runs on premium unleaded (recommended).