Mercedes-Benz S600 (1994-2000) Engine Crankshaft Position Sensor Guide
Understanding why your S600 V12 might stall when hot and how to choose the right replacement sensor.
- A common failure symptom is the engine stalling when hot and restarting after it cools down.
- Bosch is the original equipment manufacturer; using a Bosch-branded sensor is highly recommended for reliability.
- A failing sensor is a critical issue that can leave you stranded with a car that will not start.
- The sensor is located in a tight spot on the back of the V12 engine, making replacement challenging.
Is Your S600 Stalling or Hard to Start? It Could Be the Crankshaft Sensor.
The W140 S600 is a sophisticated machine, but it's not immune to common sensor failures. One of the most frequent issues that can leave you stranded is a bad crankshaft position sensor (CPS). This sensor lives in a harsh environment near the engine's bell housing, where heat and vibration eventually take their toll. When it starts to fail, it often does so intermittently, especially when the engine warms up. This can cause sudden stalling in traffic, which is both frustrating and dangerous.
Heat is the Enemy
A classic sign of a failing CPS in these Mercedes models is that the car runs fine when cold but stalls unexpectedly after reaching operating temperature. After cooling down for 15-30 minutes, it may start again as if nothing happened. This is because heat increases the sensor's internal resistance, causing the signal to drop out.
Choosing the Right Aftermarket Sensor: Quality Matters
For a high-performance V12 engine like the one in your S600, part quality is not the place to cut corners. While many budget-friendly aftermarket sensors are available, forum discussions and mechanic experiences suggest that cheap, unbranded sensors have a high failure rate on these vehicles. An unreliable sensor can cause the same frustrating symptoms to return shortly after replacement.
Brand Tiers for Your Consideration:
- OEM-Equivalent (Highly Recommended): Bosch is the original equipment manufacturer (OEM) for many Mercedes-Benz parts from this era, including the crankshaft position sensor. Choosing a Bosch-branded sensor is the closest you can get to the genuine Mercedes part without the dealership markup. It is widely considered the most reliable option for a lasting repair.
- Reputable Aftermarket: Brands like Delphi and Standard Ignition (SMP) have a long history of producing quality electronic components. While not the original part, they are generally considered a reliable alternative to the OEM-equivalent option if Bosch is unavailable.
- Budget-Friendly Options: Brands like Dorman, Walker, and various private labels offer sensors at a much lower price point. While tempting, be aware that the quality can be inconsistent. For a flagship vehicle like the S600, using a budget sensor is a gamble that could lead to repeated repairs.
Pro Tip: When replacing the sensor, it's a good idea to apply a small amount of dielectric grease to the electrical connector's seal to keep out moisture. Also, check the wiring and connector for any signs of damage or corrosion, as this can mimic the symptoms of a failed sensor.
Known Issues, Recalls, and Bulletins
A search of the National Highway Traffic Safety Administration (NHTSA) database and technical service bulletins (TSBs) did not reveal any specific recalls or widespread service campaigns for the crankshaft position sensor on the 1994-2000 Mercedes-Benz S600. However, the failure of this part is a well-documented issue across many Mercedes-Benz models of the era due to heat and age.
Frequently Asked Questions (FAQ)
What are the most common symptoms of a failing CPS on my S600?
The most common symptoms include the engine stalling when it gets hot, difficulty starting or a no-start condition, rough idling, engine misfires, and the Check Engine Light illuminating. You may also notice reduced power and poor acceleration.
Where is the crankshaft position sensor located on the S600?
The sensor is located on the driver's side of the engine, at the back where the engine meets the transmission bell housing. Access can be tight. 🎬 See how to easily locate and change the sensor. Some forum users report that the V12 engine has two sensors and that replacement can be difficult, sometimes requiring removal of the intake manifold for access.
🎬 Watch a demonstration of replacing the first of two sensors.Can I replace this sensor myself?
DIY replacement is possible for those with mechanical experience, but it can be challenging due to the tight location. It typically requires working by feel with an E8 external Torx socket and extensions. Given the difficulty, some owners may prefer to have a professional mechanic perform the replacement.
🎬 Watch this step-by-step DIY guide for replacing the sensor.Why should I buy a Bosch sensor instead of a cheaper one?
Bosch was the original supplier to Mercedes-Benz for this part. Owners and mechanics report that cheaper, non-OEM sensors can fail quickly, leading you to do the job twice. For a critical component that can leave you stranded, investing in the quality and reliability of an OEM-equivalent part is highly recommended for this vehicle.
Helpful Videos
Technical Specifications
OEM Part Numbers: A0031532128 0031532128 0031531328 A0031531328 0031532328 A0031532328 0031532528 A0031532528
The S600's M120 V12 engine may utilize two crankshaft position sensors. The sensor is typically an inductive type, held in place by a single E8 external Torx bolt. It is located on the driver's side of the engine block near the transmission bell housing.
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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 S600:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your S600 Stalling or Hard to Start? It Could Be the Crankshaft Sensor.
- Heat is the Enemy
- Choosing the Right Aftermarket Sensor: Quality Matters
- Brand Tiers for Your Consideration:
- Known Issues, Recalls, and Bulletins
- Frequently Asked Questions (FAQ)
- 🎟️ Get 5% Off