2012 Mercedes-Benz S400
The 2012 Mercedes-Benz S400 Hybrid is a luxury sedan that combines a gasoline engine with an electric motor for improved fuel efficiency. The S400 Hybrid features a 3.5L V6 engine paired with an electric motor producing a combined 302 horsepower and 273 lb-ft of torque. Other engine options for the 2012 S-Class include the S350 BlueTEC, S550, S63 AMG, and S65 AMG. Transmission options vary depending on the engine but commonly include a 7-speed automatic. Owners often praise the S400 for its comfortable ride, luxurious interior, and advanced technology. Some common complaints include the hybrid system’s complexity and potential for expensive repairs, as well as the car’s overall maintenance costs.
Electric Motor
- Battery Failure
- Description/Symptoms: Decreased fuel economy, reduced electric driving range, warning lights on the dashboard, and in some cases, complete failure of the hybrid system.
- Solution: Replacement of the hybrid battery pack.
- Estimated Cost to Fix: $8,000 - $15,000+
- Recalls: None Found
- Hybrid System Malfunction
- Description/Symptoms: Warning lights, reduced power, and the car may switch to gasoline-only operation or shut down completely.
- Solution: Diagnosis and repair of the hybrid control module or other components within the hybrid system.
- Estimated Cost to Fix: $500 - $5,000+ (depending on the component)
- Recalls: None Found
Engine
3.5L V6 Hybrid
- Oil Leaks
- Description/Symptoms: Oil spots under the car, burning oil smell, low oil level. Can occur at various seals and gaskets.
- Solution: Replace leaking seals and gaskets.
- Estimated Cost to Fix: $200 - $1,500+ (depending on location)
- Recalls: None Found
- Camshaft Adjuster Solenoid Failure
- Description/Symptoms: Rough idling, poor performance, check engine light.
- Solution: Replace the faulty camshaft adjuster solenoid(s).
- Estimated Cost to Fix: $300 - $800+
- Recalls: None Found
Transmission
7-Speed Automatic (7G-TRONIC)
- Rough Shifting
- Description/Symptoms: Harsh or delayed shifts, particularly between certain gears. Can be more pronounced when the transmission is cold.
- Solution: Fluid flush and filter change may help. In severe cases, valve body repair or replacement may be needed.
- Estimated Cost to Fix: $300 (fluid flush) - $3,000+ (valve body)
- Recalls: None Found
- Torque Converter Issues
- Description/Symptoms: Shuddering at low speeds, particularly during light acceleration. Can also manifest as a clunking noise.
- Solution: Torque converter replacement.
- Estimated Cost to Fix: $1,500 - $3,000+
- Recalls: None Found
Suspension
- Airmatic Suspension Failure
- Description/Symptoms: Vehicle sagging on one or more corners, air compressor running constantly, “Vehicle Too Low” warning message.
- Solution: Replacement of the air struts, air compressor, or valve block. Leaks in the air lines can also occur.
- Estimated Cost to Fix: $500 - $2,500+ per strut, $500 - $1,500 for compressor
- Recalls: None Found
- Airmatic Compressor Failure
- Description/Symptoms: The Airmatic compressor can fail due to leaks within the system causing the compressor to overwork itself. Symptoms can also include the vehicle taking a long time to rise to the appropriate height, or not rising at all.
- Solution: Replacement of the air compressor
- Estimated Cost to Fix: $500 - $1,500
- Recalls: None Found
Electrical
- COMAND System Issues
- Description/Symptoms: Freezing, unresponsive touchscreen, navigation problems, Bluetooth connectivity issues.
- Solution: Software update or replacement of the COMAND unit.
- Estimated Cost to Fix: $200 (software update) - $2,000+ (replacement)
- Recalls: None Found
- Electronic Control Unit (ECU) Failure
- Description/Symptoms: Various engine performance issues, transmission problems, or other system malfunctions. Check Engine Light illuminated.
- Solution: ECU reprogramming or replacement.
- Estimated Cost to Fix: $300 - $2,000+
- Recalls: None Found
- Door Lock Actuator Failure
- Description/Symptoms: Door locks failing to lock or unlock, requiring manual operation.
- Solution: Door lock actuator replacement.
- Estimated Cost to Fix: $200 - $500 per door
- Recalls: None Found
Exterior
- Sunroof Issues
- Description/Symptoms: Sunroof failing to open or close properly, making excessive noise, or leaking water.
- Solution: Repair or replacement of the sunroof motor, tracks, or seals.
- Estimated Cost to Fix: $300 - $1,500+
- Recalls: None Found
- Headlight Condensation
- Description/Symptoms: Moisture buildup inside the headlight housings, reducing visibility.
- Solution: Removal and resealing of the headlight lenses or replacement of the headlight assembly.
- Estimated Cost to Fix: $200 - $1,000+ per headlight
- Recalls: None Found
Interior
- Dashboard Cracking
- Description/Symptoms: Cracks appearing on the dashboard surface, particularly in hot climates.
- Solution: Dashboard replacement (expensive) or application of a dashboard cover.
- Estimated Cost to Fix: $100 (cover) - $2,000+ (replacement)
- Recalls: None Found
- Navigation Screen Delamination
- Description/Symptoms: The coating on the Navigation screen can start to peel off leaving a sticky residue.
- Solution: Replacement of the Navigation Screen or entire head unit.
- Estimated Cost to Fix: $500 - $2,000+ (depending on the solution)
- Recalls: None Found
Summary
The 2012 Mercedes-Benz S400 Hybrid presents a mix of luxury and potential maintenance concerns. The hybrid system is prone to expensive battery failures, and the Airmatic suspension can lead to costly repairs. Other issues such as rough shifting, oil leaks, and electrical problems add to the ownership costs. While the vehicle offers a comfortable and technologically advanced experience, prospective buyers should be aware of the potential for significant repair bills. The severity of these issues ranges from minor annoyances to major system failures, with repair costs varying accordingly, potentially totaling several thousand dollars over the vehicle’s lifespan.