Really odd fact that no one around here knows because 2.5s are rare and 2.5 autos are even rarer - 2.5L automatic 91+ XJs use the same JTEC ECU hardware, but it's actually a PCM on those because it controls the chrysler automatic they used (excepting 87-90 2.5/autos, which had an AW4 with a different BH+torque converter, don't know if they had a PCM or an ECU.) I didn't even know they made 2.5/autos after '90 till recently. Sadly it was a 3 speed auto (iirc the same one as a YJ/TJ got) and therefore got some stupid gearing like 3.07 or 3.55 so it could actually reach highway speed in 19 minutes or so.
Dodge fullsize vans and pickups as well as ZJs, YJs, and TJs use the same ECU/PCM hardware as XJs as well, and they all have PCMs. I'm not sure what the rare 1993.0 AW4 ZJs had, but I bet Pat/crew know, or know someone who knows.
You are 100% correct that 4.0 XJs never had a PCM however.