Datasheet [verified] — Nec B58944

It functions as an automotive engine drive chip or memory interface within the ECU.

: The OBD-II scanner cannot establish a connection with the ECU.

Because it is a specialized, manufacturer-ordered component rather than a generic consumer IC, finding standard commercial datasheets can be difficult. This comprehensive technical guide synthesizes everything an automotive engineer or technician needs to know about the NEC B58944, including its functional role, package characteristics, common faults, and replacement procedures. Component Overview and Functional Role nec b58944 datasheet

| Supplier | Part Number Offered | Additional Notes | | :--- | :--- | :--- | | | B58944 | Lists as Infineon; verify specs | | Centralitas Ecu | Circuito integrado B58944 | Verified automotive ECU supplier | | Buy360 | NEC B58944 D43256BGU-70Y | Includes Bosch body computer IC | | Mekweb (Elparts) | μPD43256BGU-70L | NEC Electronics, SO-28 package | | Win-Source | UPD43256BGU-70Y-E2 | Renesas Electronics |

: 70 nanoseconds (ns) maximum time window from address stabilization to valid data output (derived from the -70L / -70Y nomenclature). Supply Voltage ( VCCcap V sub cap C cap C end-sub ) : Normally operates on a regulated power plane. It functions as an automotive engine drive chip

| Category | Example NEC Parts | B58944 Similarity | |------------------------|-----------------------------|-------------------| | Bipolar transistor | 2SB589 (PNP, if existed) | Possible, but no record of 2SB589 | | Diode array | D58944 | Not standard | | Custom ASIC / Hybrid | B5xxxx series (some hybrids) | Most likely | | Date/lot code | B58944 on package surface | Not a datasheet part number |

NEC used various alphanumeric codes for different product families. The "B58944" designation does not follow NEC’s typical transistor (e.g., 2SA, 2SC) or logic IC (e.g., µPD) prefixes. Instead, it likely falls into one of three categories: | Category | Example NEC Parts | B58944

Persistent misfires on isolated engine cylinders that cannot be fixed by swapping spark plugs or coils.