Nec B58944 Datasheet Hot Jun 2026
Whether it's functioning as a high-side driver for fuel injectors, an SRAM memory for critical data, or an LDO voltage regulator, its presence is pervasive. Understanding its potential applications, identifying symptoms of failure, and sourcing it from the right place are key to any successful ECU repair. Always treat the B58944 as a component that demands respect and precision, as its proper operation is fundamental to the vehicle's performance and reliability.
The ECU cannot read the immobilizer code or fuel map.
Diagnostic Trouble Codes (DTCs) pointing toward internal ECU hardware errors. Sourcing and Repairing the B58944
The first thing one notices upon opening the B58944 datasheet is the sheer density of information. Unlike modern, web-based documentation that often relies on interactive diagrams and simplified tooltips, the B58944 datasheet is linear, exhaustive, and unapologetically technical. nec b58944 datasheet hot
Powering idle air control valves and throttle body mechanisms.
OBDII scanners cannot connect to the engine management system.
: It is identified as an "easily damaged part" on ECU circuit boards. Internal shorts can cause rapid heat buildup before the chip fails entirely. Circuit Stress Whether it's functioning as a high-side driver for
Replacing an empty or damaged NEC B58944 requires proper surface-mount soldering skills, as dealing with multi-layer automotive PCBs can quickly ruin the entire control unit. Step 1: Pre-Diagnostic Verification
: With the board unpowered, use a digital multimeter in diode mode to test output channels relative to the Ground pins. A reading near 0.00V indicates a blown silicon gateway.
The NEC B58944 component has various applications in: The ECU cannot read the immobilizer code or fuel map
It is most commonly found in the following electronic control platforms:
: The chip is typically replaced with an "empty" version (no program data is stored on the SRAM itself; it acts as temporary workspace for the ECU processor).
When replacing a burnt B58944 IC, use a professional hot-air rework station set between with a medium air velocity. Ensure you apply a high-quality, tacky chip flux to prevent bridging across the tight 28-pin grid. Always clean the trace pads with copper desoldering braid before mounting the replacement component.
Note: I assumed missing numeric values; if you want exact specs (VDS, ID, RθJA, RθJC, RDS(on), Tj max), I can fetch the official NEC datasheet and fill them in.
Based on its identification as a D43256 series chip, the standard parameters include: : Static RAM (SRAM). Memory Density : 256K bits (organized as 32,768 words × 8 bits). Access Time : 70 nanoseconds (indicated by the "-70" suffix).
