Introducing the GM PROM Cross Reference Index

This PROM cross reference index provides tables that let you use a PROM identification (ID) code to identify the PROM installed in the engine control module (ECM) on most GM vehicles. The code can be either - or both - the internal "scan ID" code or the external PROM code. From the PROM identification, you can find the part number of the PROM and trace the PROM history to determine if any revised PROM's have been issued to supersede the one in the vehicle.

The PROM history for a specific vehicle lists a succession of superseding PROM's ending with the most recent PROM released as a service part for the vehicle. PROM's that were released as service parts and explained in a technical service bulletin (TSB) are listed with a description of why the PROM was issued. In most cases, the applicable TSB also is referenced.

This index lists ECM PROM's for the 1980-95 vehicles. It does not contain ID codes and part numbers for all PROM's used in all GM vehicles. NOTE: GM flash PROM's (EEPROM's) can only be updated at GM Dealerships with factory-supplied equipment. These cars will not display a PROM ID.

By following the steps outlined below, you can use the PROM index to determine if the problem you are diagnosing can possibly be corrected by installing a revised PROM. The PROM index tables are organized by model year, engine displacement, and engine code (the eighth digit of the Vehicle Identification Number). The table columns are arranged as shown below:

Example of Table Column Arrangement

SCAN PROM PROM PART SUPERSEDING TSB REFERENCE
ID CODE (BCC) NUMBER ID PART NUMBER NUMBER
(1) (2) (3) (4) (5)


9461 8958 AMU 16058955R 8290 01228290 86194


Column 1, SCAN ID:
The scan ID is the internal PROM identification number transmitted on the ECM data stream and displayed by the scanner as PROM ID. The PROM records for each year and engine are listed numerically by this scan ID.

Column 2, PROM CODE:
These are the numbers and letters marked on the top of the PROM itself. The numbers are often referred to as the "external PROM ID." The letters are often called the "broadcast code." Together they are the external PROM code.

Column 3, PROM P/N:
This is the GM part number for the PROM identified by the codes in columns 1 and 2.

Column 4, SUPERSEDING
ID PROM PART NUMBER:
Use the superseding scan ID to locate the newer PROM in the table. If the scan ID for the superseding PROM is not known, the PROM broadcast code is listed here. If the PROM is superseded by a newer PROM, that part number is listed here.

Column 5, TSB REFERENCE NUMBER
The TSB NUMBER column identifies the original TSB that released this PROM for service. Whenever possible you should refer to the TSB for additional information before changing a PROM. The bulletin may list other parts that must be installed when the PROM is changed, or it may provide additional troubleshooting information. To find a TSB, see Reading Technical Service Bulletins. Reading Technical Service Bulletins This will display all the TSB's for that particular vehicle.

EXPANDED FOOTNOTES
Here you will find SUPERSEDING SCAN ID, PROM PART NUMBERS, symptoms and additional parts that need to be replaced when servicing the PROM.