Possible causes – Dirty Oil– Engine mechanical problems– Faulty camshaft position sensor– Faulty crankshaft position sensor– Timing belt jumped Tech description There is a factory service bulletin for the following GMC models: 2004-2009 GMC Envoy2004-2009 GMC Conyon2004-2009 GMC Envoy, Canyon Factory Service Bulletin OBDII Code P0017 Symptoms – Engine Light ON (or Service Engine Soon…