Some 2017-2018 Fusion, MKZ and C-Max vehicles with 2.0L Gas/Electric engine may exhibit an illuminated MIL with DTC P013A in the Powertrain Control Module(PCM). This may be due to an exhaust system leak. Exhaust leak inspection should be conducted before performing Powertrain Control/Emissions Diagnostics PC/ED Manual diagnostic routines. Inspect for carbon soot/moisture witness marks at exhaust connections. Inspect welds including CMS Boss, flex pipe and flanges. Inspect Catalyst Monitor Sensor(CMS) threads and crush washer to confirm sensor is fully seated in pipe boss. Do not use Vacutec smoke machine to diagnose sensor leaks. Applying soapy water solution to exhaust connections including CMS threads, while exhaust flow is restricted at the tailpipe and exhaust system is pressurized at 5 PSI(do not exceed 5 PSI), will increase ability to identify and confirm leaks
