[KJP]

I started researching the ECM label when I found a error in the NCRS 90-91 Judging Guide. They had the wrong service number (part #) listed for the L98 and B2K. The service/part# for the L98 & B2K is 01227727 and the ZR-1 90-91 has a service/part # of 1220331.

Up until 94 the ECM had a removable plug-in prom. Starting with 94 the ECM was a sealed unit with a programmable prom.

The 4 letter BCC in the upper right corner is specific to model year, engine, transmission and rear end gear. The third line is, as mention, an internal Delco part number which has no reference to any numbers in the GM parts book.

I have attached a PDF that shows the anatomy of the ECM label which was used from 90 to 93 and a few pages from the GM parts book. I also have a number of pics of ECM labels that I've collected so far and will upload them later.

I forgot to mention that the last four digits of the six numbers in the first part of the bar code on line 2 is the prom scan ID.

Ken