DTC P0634-4B: PCM/ECM/TCM Internal Temperature A Too High - Over temperature: Action

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2015 Jaguar XKR-S, 2015 Jaguar XKR, 2014 Jaguar XKR-S, 2014 Jaguar XKR, and 2013 Jaguar XKR-S. However, it is still accessible from the selected car via links, so may be relevant.

Clear the DTC. With the ignition off, wait 10 minutes and re-check DTC
Check the engine control module does not have additional external covering or obstructions which may cause overheating
Check and install a new engine control module as required. Refer to the warranty policy and procedures manual, or determine if any prior approval program is in operation, prior to the installation of a new module/component