If you just power it up it will say either "err2" or "err3", one means "can't see the TPS" and the other means "can't see the RC servo", can't remember which is which. Or it may say "off" which means it thinks the run switch is in the "off" position.

But you'll achieve nothing, to know it's a working PGM you've got to confirm it works the powervalves.
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