Family and processor
This index covers selected Bosch Motronic 4 designations. Bosch's Automotive Electrics and Automotive Electronics, page 199, figure 3, illustrates M4.3 with an 80C517 and M4.4.1 with an 80C517A. Siemens describes the SAB 80C517 as 8051-compatible. These examples use an Intel 8051-compatible architecture; this does not mean that Intel manufactured every physical MCU or that every M4 ECU has the same device.
The Bosch vehicle component catalogue identifies M4.3 and M4.4 in particular Volvo applications. Some other M4 variants are indexed as candidates where the available source identifies the designation but not its processor. Check each variant page for the evidence and its limits.
Identification
Keep the complete ECU and vehicle-manufacturer part numbers, engine code, market, year, hardware and software identity. Verify the processor marking for the actual unit. Similar names do not establish interchangeable connectors, files or programming methods.
Sources
- Bosch Automotive Electrics and Automotive Electronics, page 199, figure 3, independent mirror.
- Siemens SAB 80C517/80C537 user manual, 8051 compatibility, independent mirror.
- Bosch electronic fuel injection vehicle component applications, Volvo entries, independent mirror.
- Chiptuner-Datenbank: control units, M4 designation listings. Sources accessed 10 November 2026.