That's not good.

Time for an ECM. (We had old used "known good" ECMs in a shop cabinet, that we could quickly and temporarily attach to an engine's wire loom, and retest or start an engine, if it tested fine and ran with a used "known good" ECM, then you would reattach the engine's original ECM and see if it still "failed" or didn't start. If original ECM failed again, then we felt comfortable to tell customer his engine would require a New ECM) Edit: During this, we would be using a 70 pin CAT 12 volt bypass harness, with battery clips going to Battery + and Battery - and an additional toggle switch (12 VDC from Battery +) to ignition pinout = this eliminates the OEM truck's wiring system and any problems it might be creating. This By-pass harness also had a 9 pin Data connector, too; to attach the CAT Com. adapter

I know CAT was putting in a "test Mode" on some of their newer ECMs, where you had to program the New ECM to "test mode" and then you had 24 hours of "Electric time" or "Key ON" time before the new ECM was permanently configured to that engine serial number, interlock code, and its particular software. (This allowed for it to be credited, back to parts dept, IF the new ECM didn't cure the problem)  This was only allowed when mechanic initially programmed "test mode" into a NEW ECM, right from the beginning. = CAT truck shop foreman made everyone do this, even if they were positive that a New ECM would cure the problem, this gave a "24 hour cushion" to be able to return that ECM, if something didn't go as planned.

Note: if an ECM is in "Test Mode", then its software can still be changed to a different HP rating and serial number and interlock code, for another different engine, if it was returned to parts dept.

2nd note: you can even "reset Test Mode" ; I believe, to restart the "24 hour timer" (like if a person got an new ECM and it was already in "test mode" but only had 7 hours remaining, it could be reset, to 24 hours, again)