Some vehicles may exhibit a no start condition with an illuminated malfunction indicator lamp (MIL) and a DTC P161A after PCM replacement. This may be due to the parameter reset procedure not being properly completed. To clear this DTC, use the Ford Integrated Diagnostic System (IDS) service tool or Ford J2534 Diagnostic Software, select - Toolbox - Body - Security - PATS Functions - Parameter Reset. Follow the on-screen instructions to complete the procedure. This procedure will transfer the existing Key ID information between the modules without the need of having 2 programmed PATS keys present. There is no need to program keys when the PCM is going to be replaced. Additional information can be found in the Workshop Manual (WSM), Section 419-01. Missing or lost keys are not warrantable.