Nissan P155b00 -

The error code P155B00 in Nissan vehicles (typically the Kicks, Versa, or Sentra) indicates a Grille Shutter Performance issue [1, 2]. Specifically, the engine control module (ECM) has detected that the Active Grille Shutter (AGS)—a system that opens and closes slats in the front bumper to manage aerodynamics and engine cooling—is not operating within its expected parameters [2, 3]. What is the Active Grille Shutter System?

For reliable replacement parts, you can check retailers like eEuroparts.com or AutoZone, though you should verify the exact part number against your specific engine VIN. nissan p155b00

Illuminated Check Engine Light: The most immediate sign that the ECM has flagged a fault. The error code P155B00 in Nissan vehicles (typically

Diagnosing this code requires a departure from the "parts cannon" mentality. An inexperienced mechanic might immediately replace the throttle body assembly, only to have the code return a week later. The root cause often lies in the peripherals. A frequent culprit in Nissan vehicles is the ETC relay located in the Intelligent Power Distribution Module (IPDM) under the hood. Over time, the relay’s contacts can become pitted or loose, causing the 5-volt reference signal to flicker. Furthermore, the wiring harness that routes near the engine block is susceptible to heat stress; microscopic cracks in the insulation allow voltage to bleed to ground only when the engine reaches operating temperature and vibrates at a specific frequency. Remove each bus bar

• Remove each bus bar.
• Clean contact surfaces with a battery terminal cleaner or fine-grit sandpaper.
• Apply a thin layer of dielectric grease or conductive anti-corrosion paste.
• Re-torque bolts to factory spec (typically 5–8 Nm).
• Clear codes and perform a "BMS Reset" via the scan tool.

—typically points to an issue with the NOx (Nitrogen Oxide) Sensor A.