Per the title, is there a way to bench test whether an ECM/ECU/PCM is working properly? Here is my situation:

Vehicle: 92 Chev S10 4x4 with ECU 16144288 BCC BARL
Want to install: PCM 16168625 BCC BBMW out of a '93 Sierra

As part of this upgrade, I have fashioned a temporary jumper which enables me to install my 8625 without repinning the original 4288 harness and allows me to switch easily between the two computers.

I have wired the jumper using pin listings found on this site for going from a 7747 to 8625. I have checked continuity of the 4288 pins to the 8625 harness and they check out fine.

My dilemma is I purchased my 8625 on eBay some time ago and don't know for sure if it is working. As I pursue this computer upgrade, I don't want to install and have two questionable or malfunctioning components--PCM and jumper--which would totally complicate any troubleshooting efforts.

Thus, is there a way to test the PCM while not installed in the vehicle?

Thank you in advance...