The 2011 BMW 335d is a rare gem—a diesel-powered sport sedan offering excellent torque, solid fuel efficiency, and the premium feel you expect from BMW. It’s powered by the 3.0L twin-turbo diesel (M57) engine and designed to meet U.S. emissions standards with the help of a complex system of sensors, injectors, and after-treatment devices. While the power and efficiency are impressive, the 335d comes with its share of maintenance headaches. Below, you’ll find the most common problems associated with the 2011 BMW 335d, what symptoms to look for, and the average repair costs involved.
Is the 2011 BMW 335d Reliable?
Yes and no. Mechanically, the M57 engine is very durable. But the emissions components are prone to failure, especially as the car ages and accumulates mileage. Many 335d owners enjoy long-term reliability once the emissions-related systems are updated, deleted (off-road use only), or maintained correctly. However, neglect or poor diesel quality can result in expensive problems quickly.
Most Common 2011 BMW 335d Problems
1. Clogged Diesel Particulate Filter (DPF)
The DPF captures soot from the exhaust and periodically burns it off through regeneration. If this process is interrupted, it becomes clogged and severely limits engine performance.
- Symptoms: Loss of power, limp mode, check engine light
- Fix: Forced regeneration or DPF replacement
- Cost: $1,000–$3,000 depending on replacement or cleaning
2. NOx Sensor Failure
NOx sensors measure nitrogen oxide levels before and after the SCR system. They are known to fail due to heat and age.
- Symptoms: Poor performance, check engine light, increased DEF usage
- Fix: Replace upstream or downstream NOx sensor
- Cost: $500–$850 per sensor
3. DEF System Malfunctions (Diesel Exhaust Fluid)
The DEF system helps convert NOx emissions into harmless nitrogen and water. The injector, tank heater, or pump can fail, leading to emissions faults and limp mode.
- Symptoms: Emissions warning lights, no-start countdown, excessive DEF consumption
- Fix: Replace faulty component; clear faults
- Cost: $400–$1,200 depending on the part
4. EGR Valve and Cooler Issues
Exhaust gas recirculation systems lower combustion temps but can become clogged with soot over time, especially with stop-and-go driving.
- Symptoms: Rough idle, low power, check engine light
- Fix: Clean or replace EGR valve and cooler
- Cost: $600–$1,500
5. Intake Manifold Swirl Flap Failure
Swirl flaps are small valves inside the intake manifold. If they break, they can fall into the combustion chamber, causing catastrophic engine damage.
- Symptoms: Misfires, intake codes, loud ticking
- Fix: Remove or delete swirl flaps (popular preventive fix)
- Cost: $400–$800
6. Transmission Problems (ZF 6-Speed Automatic)
The 6HP automatic transmission is strong but suffers if fluid isn’t changed regularly, despite BMW’s “lifetime fluid” marketing.
- Symptoms: Harsh shifts, hesitation, gear slipping
- Fix: Transmission fluid and filter service; rebuild if severe
- Cost: $500 for service; $3,000+ for rebuild
7. Turbocharger Actuator Issues
The 335d uses two turbos—one for low-end and one for high-end power. Actuator issues can cause the turbo to stick or perform poorly.
- Symptoms: Boost loss, underboost codes, sluggish acceleration
- Fix: Repair or replace actuator; inspect vacuum lines
- Cost: $600–$1,200
8. Battery Drain and IBS Sensor Failure
The intelligent battery sensor (IBS) can malfunction, leading to excessive draw or charging problems.
- Symptoms: No-start, low battery warning, dead battery overnight
- Fix: Replace IBS sensor or battery; register new battery
- Cost: $300–$500
9. Glow Plug Module and Plugs
Essential for cold starts, glow plugs and their control module can fail after years of use.
- Symptoms: Hard cold starts, engine misfires in cold temps
- Fix: Replace glow plugs and controller
- Cost: $500–$900
Typical 335d Fault Codes to Watch For
| Code | Description |
|---|---|
| P20EE | SCR NOx Catalyst Efficiency Below Threshold |
| P229F | NOx Sensor Circuit Performance Bank 1 Sensor 2 |
| P0401 | Insufficient EGR Flow |
| P0671–P0676 | Glow Plug Circuit Faults |
Preventive Maintenance Tips
- Use high-quality diesel fuel and add cetane boosters if needed
- Drive long enough for the DPF to regenerate—avoid excessive short trips
- Flush transmission fluid every 60,000 miles
- Monitor DEF levels and avoid letting the system run dry
- Scan for codes monthly using a BMW-compatible OBD2 scanner
Average Repair Costs
| Problem | Estimated Cost |
|---|---|
| NOx sensor (each) | $500–$850 |
| DPF cleaning/replacement | $1,000–$3,000 |
| EGR valve and cooler | $600–$1,500 |
| DEF pump or injector | $400–$1,200 |
| Transmission service | $500–$800 |
| Glow plugs and controller | $500–$900 |
Final Thoughts
The 2011 BMW 335d is a rewarding car for the right owner—powerful, efficient, and fun to drive—but it comes with diesel-specific complexities that require attention. Most problems stem from emissions-related systems designed to meet strict U.S. standards. If you’re willing to invest in preventive maintenance, keep up with diagnostics, and possibly consider emissions modifications (for off-road use), the 335d can be a fantastic long-term car.
Tip: Always get a pre-purchase inspection focused on emissions components if buying used. And if you already own one, consider servicing the DPF, EGR, and sensors before they trigger costly faults.