Mercedes Crankshaft Position Sensor - Genuine Mercedes 6429050000

Product Information

The engine crankshaft position sensor monitors the position and rotational speed of the crankshaft, providing information to the engine control unit (ECU). The sensor ensures proper timing for fuel injection, ignition, and other key engine functions. Without accurate crankshaft data, the ECU can't adequately time the spark or fuel, causing poor performance or even preventing the engine from running. Crankshaft position sensors come in different designs, with magnetic or Hall-effect sensors being the most common. The magnetic sensor consists of a coil and magnet that generates a signal as the engine rotates, while the Hall-effect sensor uses a semiconductor to detect changes in the magnetic field.

The crankshaft position sensor is usually located near the crankshaft pulley/harmonic balancer, or flywheel/transmission depending on the engine’s design. It works by detecting notches or teeth on a component called a reluctor or tone wheel, creating a signal that the ECU can interpret. When this sensor fails, common symptoms include engine stalling, rough idling, misfires, or the engine not starting at all. One of the most frequent failure modes is internal short-circuiting due to heat and vibration over time. Contaminants like oil, dirt, or metal shavings can also interfere with its ability to detect the crankshaft's position.

• No Start Condition: The CPS gives the information to the ECU that the engine is showing positive RPM and is ready to start. If the computer does not get a signal from the sensor, or the sensor is outputting values that it is not anticipating, the engine won’t start.
• Stalling when warm: Once the engine warms up, a failing crankshaft position sensor can often cause stalling when coming to a stop because the engine doesn’t have the right information to maintain a stable idle.
• Dead or erratic tachometer: Some older vehicles may run the tachometer off of the output from the crankshaft sensor. If the tach is behaving strangely, especially in conjunction with other running problems, the CPS could be at fault.
• P0335: If the integrity of the internal wiring has failed, you may get a P0335, however it is not a guarantee that a vehicle with a failing CPS will have a check engine light.
• Poor performance at certain RPMs: A failing crankshaft position sensor can cause issues with engine performance, especially if at a certain point in the rpm range the sensor can’t send an in-range signal to the ECU with may cause timing to drift. Failing crank position sensors more commonly cause running issues at higher RPMs and idle.
• Misfires across multiple cylinders: If the engine is struggling to time fuel and spark, you may encounter misfires across all cylinders at once. This is in contrast to the failure of a coil or fuel injector, which may only effect one cylinder at a time.

About Genuine Mercedes

The original parts used by Mercedes Benz to build your car are available as replacement parts under the “Genuine Mercedes Benz” brand. Manufactured under the direction of Mercedes Benz, expect excellent quality and a premium price since these parts are exclusively available through the Mercedes Benz Dealership network.

You may not realize this, but the parts that make up your Mercedes-Benz are not necessarily manufactured by Mercedes-Benz. No cause for concern, as Mercedes-Benz designs the part, hires a manufacturer, and ensures its quality to you. In fact, many of these manufacturers have been making parts for Mercedes-Benz for decades. In our industry these manufacturers are called OEM (Original Equipment Manufacturers), and these are often brands you recognize, including Lemforder, ZF, Sachs, Bosch, Valeo, Zimmermann, Siemens VDO, Corteco, and more. Don’t be surprised to open that Genuine Mercedes-Benz parts box and find an OEM branded part inside, simply with the addition of a Mercedes-Benz logo.

Be sure to keep an eye out for OE tags on our product pages to quickly identify parts coming direct from OE manufacturers. That extra bit of insight could save you some serious money while shopping! Refer to our OE Academy for further information regarding the OE/OEM tags throughout the site.