Nec B58944 Datasheet -

The "B58944" designation is a Bosch-specific house part number. The original manufacturer part is the NEC $\mu$PD43256BGU-70Y Component Type : 256K-bit CMOS Static RAM (SRAM). Configuration : 32K words : SOP-28 (Small Outline Package with 28 pins). Speed Grade : 70ns access time (indicated by the "-70" suffix). Supply Voltage : Typically 5V (standard for the $\mu$PD43256 series). Datasheet Documentation NEC B58944 D43256BGU-70Y BOSCH Auto ECU computer IC

The B58944 is known as an "easily damaged part" on Auto ECU circuit boards. When this chip fails, it can cause various engine issues, including: Complete ECU failure (no start). Erratic engine behavior or "limp mode." Loss of stored diagnostic data. nec b58944 datasheet

Typical application & context