Some 2017-2018 Lincoln MKZ vehicles with 2.0L gas/electric (hybrid) engines may exhibit a MIL on with DTC P013A in the PCM. This may be due to an exhaust system leak. Exhaust leak inspection should be conducted before performing powertrain control/emissions diagnostics.
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 that the sensor is fully seated in the pipe boss.
Do not use the 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 the exhaust system is pressurized at five psi will increase the ability to identify leaks (do not exceed five psi).
