was the use of a MAF instead of AFM in the Motronic 1.5. 1.5.4 Was used since 1994 in the Opel Omega B with X20SE engine. (Modified successor of C20NE engine) Major change to the Motronic 1.5.2 was the use of DIS ignition system, knock sensor and EGR valve. Was also used in the Opel engine X22XE. M1.5.5 Used in Fiat/Alfa/Lancia and Opel vehicles. 1.7 The key feature of Motronic 1.7 is the elimination of an ignition distributor, where instead each cylinder has its own electronically triggered ignition coil. Motronic 1.7 family has versions 1.7, 1.7.2, 1.7.3, all of them used on M42/M43 engines in BMW 3 Series (E36) up to 1998 and BMW 5 Series (E34) up to 1995. The BMW M70 12 cylinder had the Motronic M1.7 and two distributors. 1.8 This system was used by Volvo on the B6304 engine used in the Volvo 960. Motronic 2.x Motronic M2.x is powered by various i8051 derivatives made by Siemens, usually SAB80C515 or SAB80C535. 2.1 The ML 2.1 system integrates an advanced engine management with 2 knock sensors, provision for adaptive fuel & timing adjustment, purge canister control, precision sequential fuel control and diagnostics (pre OBD-1). Fuel enrichment during cold-start is achieved by altering the timing of the main injectors based on engine temperature. The idle speed is also fully controlled by the digital Motronic unit, including fast-idle during warm-up. Updated variants ML 2.10.1 through 2.5 add MAF Mass Air Flow sensor logic and direct fire ignition coils per cylinder. Motronic 2.1 is used in the Porsche 4 cyl 16V 944S/S2/968 and the 6 cyl Boxer Carrera 964 & 993, Opel/Vauxhall, FIAT & Alfa Romeo engines. 2.3/2.3.2 The M2.3.2 system was made for Audi's turbo 20V 5-cylinder engines mainly, but a variant was also used on the Audi 32V 3.6L V8 and a few Audi 32V 4.2 V8 engines. The turbo 5 cylinder version was the first time knock and boost control had been introduced in one ECU, though the ECU was really two computers in one package. One side of the ECU controlled the timing and fueling while the other side controlled the boost and knock control. Each side has its own Siemens SAB80C535 processor and its own EPROM for storing operating data. What made this ECU special was the use of two crank sensors and one cam sensor. The ECU used one crank sensor to count the