For those having issues with your exhaust tailpipe actuator: Aug 26 2016 3596 - 2016 - 2017 Mustang Shelby GT-350 - P26FE Diagnostic Trouble Code (DTC) And Parts Availability Some 2016 - 2017 Mustang Shelby GT350 vehicle may exhibit a P26FE DTC with diagnostics leading to replacement of the Exhaust Tailpipe Actuator. This part was not initially released for service. This part is now available for service and Workshop Manual Procedures are now available in section 309-00D. The service partno. is FR3Z-5K245-A.