I finally got a cable and have been trying to diagnose a problem when i noticed something peculiar. I have a 1227730 ECM but the prom id shows up as a 5181. Now in all my research I can not find anywhere that this prom was ever put into that ecm. I have found 1990 cars with that ecm, and i have found 1990 cars with that prom id. but never together, and my car is a 1991.

So i am now all kinds of confused on what the PO could have done to my car.

 

The PROM ID isn't definitive. Look at the MEMCAL and on top of the PROM should be a silver sticker. Post the 4 letter code that is on it here in this thread.

RBob.

 

1991 z28 5.7

Ecm 7-7730
Calibration 1201MT
Prom Delco ANJF 4307

 

OK, it is a L98 f-body PROM/MEMCAL. However it was a May 1989 release for the '90 MY.

The numbers you listed match up with that PROM (4307 & the 5181 scan ID).

AUJP superseded that PROM, as it is the latest release (March of 1990). They are both f-body L98 with 700R4 transmission.

RBob.

 

Thanks for the info I appreciate it. So I can leave it alone and it will work just fine?

 

Yes & no. Calibrations are usually superseded due to drive-ability issues or false SES/CEL light. Sometimes it is done for emissions reasons.

RBob.

 

So getting the proper prom would probably be a good idea and it may solve some of my issues.