Chrysler 2.2 & 2.5 Engine - Engine Computers

Engine Computers

Various kinds of Engine Control Units were used with the 2.2 and 2.5 engines. From 1984–1987, the ECU was divided into the Logic Module (LM), which was inside the passenger cabin, and the Power Module located near the battery on the left front fender. The LM used a Motorola 6803U4 processor operating at 1 MHz, with 256 bytes of RAM and either two 8K EPROMs or one 16K EPROM. From 1988–1989, a SMEC (Single Module Engine Controller) was used. This was a complete redesign of the older system, using modern CAD for board design, and higher density SMD components. The processor was a 68HC11 operating at 2 MHz with 256 bytes of RAM and a 32K EPROM. Functionally, the SMEC was the combination of the earlier Logic and Power modules into one unit. Starting in 1990, a more advanced SBEC (Single Board Engine Controller) was used, which integrated the earlier two board computer into a single board.