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Location and use of the engine RPM sensor of the Smart Fortwo 451

Model: Smart Smart 451 - Years 2007-2015
Part: Crankshaft position sensor

In this video, we can see where the crankshaft speed sensor is located on a Smart 451. It is positioned near the crankshaft pulley, on the side of the flywheel, and it serves to detect the position and speed of the crankshaft, providing the ECU with precise information about the angle of the crankshaft (to synchronize injection and ignition) and how many revolutions per minute the engine is running. Therefore, in diesel engines like the one in the video, it regulates the timing of the diesel injection. If the sensor is faulty or dirty, we may notice that the engine does not start, or there may be intermittent ignition, a loss of power, and a check engine light with error codes such as P0335, P0016, or P0340.

Posted on 29 December 2025 by ScegliAuto

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