Mercedes-Benz ML320 (1998-2009) Engine Camshaft Position Sensor Guide
Diagnose and fix stalling, no-start, and rough idle issues by choosing the right camshaft position sensor for your ML320.
- A failing camshaft sensor will cause a check engine light, stalling, and no-start conditions.
- For best results, choose an OEM or premium aftermarket brand like Bosch, as cheap sensors are known to be unreliable.
- Replacement is a simple DIY task that takes less than 30 minutes with basic tools.
- Always replace the sensor's O-ring to prevent common oil leaks from this location.
Is Your ML320 Camshaft Position Sensor Failing?
A failing camshaft position sensor on the M112 V6 engine in the 1998-2003 ML320, or the later M272 V6 in the 2007-2009 models, will cause noticeable problems. The most common symptom is the Check Engine Light illuminating on your dashboard. Other serious signs include the engine cranking but refusing to start, or starting only after a long crank time. You may also experience sudden engine stalling, a rough and shaky idle, hesitation when accelerating, and a general loss of power. These issues occur because the engine's computer is guessing when to fire the spark plugs 🎬 Watch: Common symptoms of a failing camshaft position sensor and injectors.
Known Issue: Oil Leaks
A very common issue on the Mercedes M112 and M113 engines is for the O-ring on the camshaft position sensor to degrade over time, causing a small oil leak. When you replace the sensor, it is critical to also replace this O-ring to prevent future leaks. 🎬 See how to replace the sensor O-ring to stop oil leaks Many new sensors come with a new O-ring included.
Choosing the Right Aftermarket Sensor for Your ML320
When it comes to critical engine sensors for a Mercedes-Benz, part quality matters. While budget-friendly options are available, forum users and mechanics often report that ultra-cheap, generic sensors can be unreliable and fail prematurely. For a part this critical and easy to replace, investing in a quality brand is a wise decision.
Brand Quality Tiers
- Tier 1: OEM / Premium OE Brands: Bosch is a well-known Original Equipment Manufacturer (OEM) for Mercedes-Benz, and their aftermarket sensors are considered a top choice for reliability and performance. Other premium brands in this category include Hella and Vemo. These parts are expected to match the fit and function of the original sensor perfectly.
- Tier 2: Reputable Aftermarket Brands: Brands like Delphi, Standard Ignition (SMP), and Walker Products have a solid reputation for producing quality engine management components that offer a good balance of price and reliability. These are a dependable choice for most owners.
- Tier 3: Economy Brands: This category includes brands like Dorman, Spectra, and various other private-label brands. While they are the most affordable, their long-term reliability can be inconsistent for sensitive electronics. They can be a viable option for a tight budget, but be aware that you may be replacing the part again sooner than you would with a premium brand.
Installation and Cost
Replacing the camshaft position sensor on an ML320 is a straightforward job that most DIYers can complete in under 30 minutes. The sensor is located on the front of the passenger-side cylinder head. It is held in place by a single external Torx bolt (size E8) and has one electrical connector.
Pro Tip: Easy Replacement
After removing the plastic engine cover, the sensor is easily accessible. Simply unplug the electrical connector, remove the single E8 Torx bolt, and gently twist and pull the old sensor out. Lightly oil the O-ring on the new sensor before inserting it, and be careful not to overtighten the small bolt.
🎬 Watch this step-by-step M112 engine sensor replacement walkthrough| Part Type | Estimated Cost |
|---|---|
| New OEM (Genuine Mercedes-Benz) | $110 - $220 |
| New Aftermarket | $17 - $97 |
| Shop Labor | $60 - $95 |
| Total Professional Replacement | $130 - $320 |
Frequently Asked Questions (FAQ)
Can I replace the ML320 camshaft position sensor myself?
Yes, this is considered a very easy DIY job. You only need basic hand tools, including an E8 external Torx socket. The sensor is easily accessible at the front of the engine, and the entire process typically takes less than 30 minutes.
Can I drive my ML320 with a bad camshaft position sensor?
It is not recommended. While the vehicle may still run, a faulty sensor can cause unexpected stalling while driving, which is a significant safety hazard. It can also lead to a no-start condition, leaving you stranded.
Where is the camshaft position sensor located on the ML320?
On the V6 engines used in the 1998-2009 ML320, the camshaft position sensor is located on the front of the passenger-side cylinder head, near the top of the engine. It is held in by one bolt.
Is the camshaft sensor the same as the crankshaft sensor?
No, they are different sensors with distinct functions. The camshaft sensor tracks the position of the camshaft for valve timing, while the crankshaft position sensor tracks the rotational speed and position of the crankshaft. While they work together, a failure in one will produce similar symptoms, but they are not interchangeable and are located in different parts of the engine.
Are there any recalls for the ML320 camshaft position sensor?
No, searches of the NHTSA database and other public records did not find any specific recalls or Technical Service Bulletins (TSBs) for the engine camshaft position sensor on the 1998-2009 Mercedes-Benz ML320.
Helpful Videos
Technical Specifications
OEM Part Numbers: A0041536928 0041536928 A0041530728 A0031538328
This is a 3-pin Hall effect sensor, typically held in by one E8 external Torx bolt.
We Have This Part in Stock
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.
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