Mercedes Benz E550 Crankshaft Position Sensor Guide (2007-2011)
If your E550 cranks but won't start, or stalls when hot, your crankshaft position sensor is a likely culprit.
- A failing sensor will likely leave you stranded; the most common symptom is an engine that cranks but won't start when hot.
- Driving is not recommended, as the engine can stall unexpectedly at any time, creating a serious safety risk.
- For this critical sensor, an OEM-quality brand like Bosch is strongly recommended over budget options for reliability.
- Replacement is a challenging DIY job due to the sensor's location at the back of the engine against the firewall.
Is Your E550 Crankshaft Position Sensor Failing?
A bad crankshaft position sensor on the 2007-2011 E550 often fails when the engine gets hot. You might drive across town without a problem, stop for a few minutes, and then find the car will crank but refuses to start. After the engine cools down for 20-30 minutes, it may start up again as if nothing happened. This intermittent failure is a classic sign. Other common symptoms include the engine suddenly stalling while driving, a rough idle, poor acceleration, and the Check Engine Light coming on.
Choosing the Right Aftermarket Sensor for Your Mercedes
When it comes to critical electronic sensors on a Mercedes-Benz, not all parts are created equal. The crankshaft position sensor is essential for the engine to run, and a low-quality part can fail prematurely, leaving you stranded again.
- OEM-Quality Brands (Bosch): Bosch is an original equipment manufacturer for Mercedes-Benz. Choosing a Bosch sensor is the closest you can get to buying the part from the dealer. It is designed to meet the exact tolerances and temperature ranges required by your E550's engine, offering the highest reliability.
- Value Aftermarket Brands (Replacement): Brands like Replacement offer a significant cost saving. While they are designed to fit and function, they may not have the same long-term durability and resistance to heat as an OEM-quality part. For a critical component like this, a value brand is a budget-conscious choice, but it may carry a higher risk of failure compared to an OEM or Bosch part.
Pro Tip: Given the sensor's critical role and the difficulty of replacement, spending a little more on an OEM-quality brand like Bosch is a wise investment for long-term peace of mind.
Known Issues: Recalls and Service Bulletins
There are no specific recalls or Technical Service Bulletins (TSBs) for the crankshaft position sensor on the gasoline-powered 2007-2011 Mercedes Benz E550 with the M273 engine. A recall (NHTSA 08V-006) was issued for this sensor on some 2006-2008 E-Class models, but it only applied to vehicles with the OM642 DIESEL engine and does not affect the E550.
| Part Type | Estimated Cost |
|---|---|
| New OEM (Dealer) | $95 - $140 |
| New Aftermarket (OEM Quality, e.g., Bosch) | $45 - $70 |
| New Aftermarket (Value Brand) | $29.68 |
| Shop Labor | $100 - $190 |
Frequently Asked Questions (FAQ)
Where is the crankshaft position sensor located on a 2007-2011 E550?
The sensor is on the driver's side (left side) of the engine, at the very back where the engine connects to the transmission bell housing. It is in a very tight space against the firewall and is difficult to see and reach from above.
🎬 See this video to help you locate and change the sensor.Can I replace the E550 crankshaft position sensor myself?
This is a challenging DIY job due to the sensor's location. It requires removing the engine covers and air intake ducts for access. You will likely be working by feel, using long extensions and a swivel socket to remove the single E8 or T30 Torx bolt. While possible for an experienced DIYer, many owners choose to have a professional perform this replacement.
🎬 Watch this step-by-step guide to see if you can DIY.What is the main symptom of a bad crankshaft sensor on this car?
The most common and definitive symptom is a "crank, no start" condition, especially when the engine is hot. The engine will turn over but will not fire up because the ECU is not receiving the signal it needs to manage ignition and fuel.
Will a bad crankshaft sensor always cause a Check Engine Light?
Usually, but not always. A failing sensor can cause stalling or no-start issues before the ECU consistently recognizes the fault and illuminates the light. If the light is on, a code scan will likely show P0335, which points directly to a fault in the crankshaft position sensor circuit.
🎬 Watch a diagnostic walkthrough for troubleshooting the P0335 code.Helpful Videos
![Fixing a Mercedes ML350 (2006) P0335 Code | Crankshaft Sensor & ECU Drama! [First MB Diagnostic]](https://img.youtube.com/vi/a_wNhpU85to/mqdefault.jpg)
Technical Specifications
OEM Part Numbers: A2729050000 A0041538728 6429050000 2729050000 0041538728
The sensor is a Hall effect or inductive sensor held in place by a single E8 or T30 Torx bolt on the driver's side of the transmission bell housing.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mercedes Benz E550: