Tech description There is a factory service bulletin for the P3138 code for the following models: 2005-2007 Audi A32005-2007 Audi A42007 Audi A4 Cabriolet2008 Audi TTAudi Factory Service Bulletin OBDII Code P3138 Symptoms – Engine Light ON (or Service Engine Soon Warning Light) AUDI Related P3138 code 2005 AUDI A3 Electrical System: Software 2005 AUDI…