ECM Interchangeability

I performed some testing and it appears that any model year ECM will work in any car. That is, a 1990 ECM will work in a 1995 and a 1995 ECM will work in a 1990. The details of the testing are described below.

At the factory, GM issued four ECM part numbers across the six model years.

01228331 1990 to 1991.

16168001 Early 1992.

16163993 Later 1992 to about 1993 1/2.

16196394 About 1993 1/2 to 1995.

I removed a factory installed 1990 01228331 from a 1990 car. Then installed a 1995 BMCB calibration chip and installed the ECM on a 1995 car. Everything worked normally. The engine went into closed loop fuel control, it went into learning mode, the EGR worked normally, the ASR worked, the momentary contact full power key worked, and the engine data scanner displayed engine rpm with a resolution of 1 rpm. The ALDL data stream ran at 6.6 frames per second, just like a 1995 ECM.

I removed a factory installed 1995 16196394 ECM from a 1995 car. I installed a 1990 AYBK calibration chip and installed the ECM on a 1990 car. Everything worked normally. The engine went into closed loop fuel control, it went into learning mode, the full power key worked. The engine data scanner displayed engine rpm with a resolution of 25 rpm. This is normal for a 1990 car. The ALDL data stream ran at 6.6 frames per second, just like a 1990 ECM.

Service part numbers:

19186070    Remanufactured unit for '92 - '93. Discontinued about 2005.

16163993    New ECM sold outright for '92-'93. Discontinued about 2006.

16196394    New ECM sold outright for all model years. Replaced 16163993. Discontinued about 2008.

88999186    Remanufactured unit. Replaces 16163993. Discontinued about November 2008. Also known as AC/Delco pn 218-00000

88961142    Remanufactured unit for '94 -'95. Discontinued about September 2008.

19152968    Remanufactured unit. Discontinued about October 2008. Also known as AC/Delco pn 371-648.