[Injuneer]

Clear the codes by pulling the "PCM BAT" fuse on the panel at the end of the dash for 30 seconds (key "off"). Â*See if the codes come back. Â*I think the EPROM code sets when their is a checksum error. Â*DTC 51 is rare with the "fixed" chip 94 and newer PCM's, since the most common error is cause by poor insertion of the chip, which is a problem more with the 93 and earlier ECM's.

As far as the DTC 41 and 42 codes, its a problem somewhere in the entire ignition system made up of the Opti, the IC Module and the IC signal that goes from the PCM to the ICM. Â*

I have the logic tables for diagnosing the codes, and can fax them to you if you want. Â*They are fairly complex because there are so many components involved. Â*Shoebox may actually have them on his Tech Pages website, as well.