This Preliminary Information communication provides information to the technician about vehicles that may have a Malfunction Indicator Lamp on. The technician may find Diagnostic Trouble Codes P0299 or P0234 set. The technician is provided with a list of causes of misdiagnosis leading to returned Turbochargers with no trouble found. The purpose of this information is to reduce the number of no trouble found (NTF) turbochargers being returned to the WPC by informing the Service Department personnel of what inspections and/or diagnosis to perform, prior to replacing and returning a turbocharger to the WPC.Â