Some 2016-2019 Ford Transit vehicles equipped with a 3.2L diesel engine may indicate a blank PCM when connected to the Ford diagnostic scan tool. Do not replace the PCM.
As a work-around to access the PCM, remove the key from the ignition for one minute. Then remove the PCM relay in the battery junction box. Reinstall the PCM power relay, insert the key into the ignition switch and turn the key to the ON position, then attempt to access the PCM.
Ford Engineering is investigating the issue.