'92 LT1 - Can't clear code 16

[LT1DRVR92]

After a shutdown, I recently replaced the Optispark with a Petris unit. Engine runs fine but I still get a code 16 and can't clear it from the CCM. I do NOT get an SES light. The ECM was rebuilt and new plugs and wires put in within the last 5,000 miles. The coolant sensor unit is also new. Is it possible that the code is somehow embedded in the CCM and can't be cleared? I would really appreciate any help and suggestions because I am afraid to drive the car very far as long as the code 16 keeps showing. Thanks.

[SQUIRMIN VERMIN 84]

I'm assuming OBD1? I think we went to OBD2 in 1994. I don't know offhand what that code is for sure, but I found this link that seems to address your problem, but not an aftermarket opti replacement. Not sure how that would affect anything since it's meant as a replacement part.

how to fix "code 16" '92 vette - Corvette Forum : DigitalCorvettes.com Corvette Forums

Hope you get a lead on this..