A Guide to the Crankshaft Position Sensor on the 2004-2011 Mercedes-Benz SL600
Don't let a common sensor failure leave your V12 twin-turbo engine unexpectedly stalled.
- A failing crankshaft sensor is a common issue that can cause your SL600 to stall or not start, especially when hot.
- For reliable performance, only use the Bosch OEM replacement part; budget brands are known to fail quickly.
- Replacement is difficult due to the sensor's location at the top rear of the V12 engine, making it a challenging DIY job.
- Driving with a faulty sensor is unsafe; have it replaced immediately if you experience symptoms like stalling.
Understanding Crankshaft Position Sensor Failure in Your SL600
The crankshaft position sensor, or CPS, is a known failure point on many Mercedes-Benz vehicles from this era, including the R230 SL600 with its M275 twin-turbo V12 engine. Due to its location, it is exposed to intense engine heat, which can cause the electronic components inside to fail over time. When it fails, it typically does so without much warning, and the symptoms are often severe enough to leave you stranded.
Symptoms of a Failing Crankshaft Position Sensor
The signs of a bad CPS are usually distinct and hard to ignore. The most common symptom is the engine cutting out once it has warmed up, and then refusing to restart until it has cooled down. Other symptoms include:
- Engine will not start: The starter will crank, but the engine won't fire up because the ECU has no crankshaft signal.
- Intermittent stalling: The engine may shut off unexpectedly while driving, which is a serious safety hazard.
- Rough idling and misfires: The engine may vibrate or run unevenly at a stop.
- Poor acceleration: You may notice a significant loss of power and sluggish performance.
- Check Engine Light: A failing sensor will almost always trigger a Check Engine Light and store a fault code, most commonly P0335.
Can I Drive with a Bad Sensor?
No. A failing crankshaft position sensor can cause the engine to stall at any time, including at high speeds or in traffic. This results in a loss of power steering and power brake assist, creating a dangerous situation. If you suspect your sensor is failing, it is not safe to drive the vehicle.
Choosing the Right Aftermarket Part
For a critical component like this on a complex engine like the M275, part quality is paramount. While many brands are available, owner communities and professional mechanics strongly recommend sticking with the Original Equipment Manufacturer (OEM).
- Tier 1 (OEM/Recommended): Bosch
Bosch is the original equipment manufacturer for Mercedes-Benz for this part. Choosing a Bosch sensor, whether from a dealer or an aftermarket supplier, ensures you are getting the exact same quality, fit, and durability as the original part. Given the difficulty of replacement, using a part you can trust to last is the smartest choice. - Tier 2 (Reputable Aftermarket): Hella, Standard Ignition (SMP)
Brands like Hella and Standard Ignition have a long-standing reputation for producing quality electronic components. In some cases, they may even be re-boxing the OEM part. These are generally considered reliable alternatives if Bosch is unavailable. - Tier 3 (Budget Options): Other Brands
There are many other brands available at lower price points. However, for a part that is labor-intensive to replace and can leave you stranded, opting for a budget sensor is a significant risk. Failures of cheaper sensors are common, often occurring soon after installation.
Pro Tip: The cost difference between a budget sensor and a Bosch OEM sensor is minimal compared to the potential cost of a tow truck or the labor to replace the part a second time. Always choose Bosch for this specific repair.
Cost to Replace the Crankshaft Position Sensor
| Part/Service | Estimated Cost |
|---|---|
| New OEM (Dealer) | $120 - $180 |
| New Aftermarket (Bosch) | $45 - $80 |
| Shop Labor | $150 - $250 |
| Total Estimated Cost (Shop) | $195 - $330 |
Cost estimates are for reference only and may vary based on location, supplier, and vehicle condition.
Frequently Asked Questions (FAQ)
Where is the crankshaft position sensor located on the 2004-2011 SL600?
The sensor is located at the back of the engine on the driver's side, mounted to the top of the transmission bell housing at about the 12 or 1 o'clock position. It is held in place by a single E8 external Torx bolt. Access is very tight due to the large V12 engine filling the engine bay.
Can I replace this sensor myself?
This is a challenging DIY job for the SL600. While the sensor itself is simple to unbolt, reaching it is difficult. It requires long extensions, a universal joint, and an E8 socket. You may need to work entirely by feel and possibly remove some intercooler piping at the firewall for better access. This job is best left to an experienced DIYer or a professional mechanic.
Are there any recalls for the crankshaft position sensor?
No. Searches of the NHTSA database and other sources show no specific recalls or Technical Service Bulletins (TSBs) for the crankshaft position sensor on the 2004-2011 SL600. Any recalls for this vehicle pertain to other components.
Will a bad sensor cause permanent engine damage?
While a failing sensor itself won't directly cause mechanical damage, it can lead to engine misfires. If ignored for a long time, chronic misfires could potentially harm the catalytic converters. The most significant risk, however, is the engine stalling while driving, which can lead to an accident.
Technical Specifications
OEM Part Numbers: A0031532828 A0031532728
The recommended replacement is the Bosch OEM sensor, part number 0 261 210 170.
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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