Hitachi KNS0003 Ignition Knock Sensor - OEM Quality

The Hitachi KNS0003 is a direct OEM-replacement ignition knock sensor designed to restore proper detonation monitoring on applicable Nissan and Infiniti vehicles. A knock sensor's job is straightforward but critical: it detects abnormal combustion vibrations (detonation or "ping") in the engine block and sends a voltage signal to the ECU, which then retards ignition timing to protect the engine from damage. When the factory sensor fails, the ECU typically defaults to a conservative timing map that robs power and fuel economy — a condition you will notice as sluggish throttle response and a persistent check engine light with P0325 or P0330 codes. The KNS0003 replaces the failed unit with a brand-new piezoelectric element built to the same OE specifications Hitachi uses as a Tier 1 supplier to the original vehicle manufacturer.

Installation is a bolt-on affair with a flange-mount design that matches the factory sensor's footprint and electrical connector exactly. On inline-four applications, the sensor is typically accessible on the side of the block and the swap takes 15-20 minutes with basic hand tools. V6 applications can be more involved, as the sensor often sits beneath the intake manifold and may require partial manifold removal for access. In either case, proper torque on the sensor bolt is essential — an improperly tightened knock sensor will either produce false readings or fail to detect genuine detonation. Once installed and the code cleared, the ECU returns to its normal timing maps, and you should notice an immediate improvement in throttle response and a return to normal fuel consumption patterns.