Code description: Diesel Particulate Filter Efficiency Below Threshold Bank 1 or Bank 2
- Decreased fuel economy
- Check engine light
- Dilution in oil
- Sluggish acceleration
What Does it Mean?
When your Volkswagen is throwing this code, there is a problem with an emission control device that eliminates soot emission from the exhaust. The diesel particulate filter, or DPF, is positioned in the exhaust system and is 98% effective in removing soot from the exhaust before it is released into the environment.
During operation, the DPF creates a small amount of back pressure. Your Volkswagen has pressure feedback sensors on the DPF in order to monitor the functionality of the filter. If the sensors pick up a discrepancy in pressure, it will throw this code.
This code is often referred to as a “soft code” because it is real time and will go away when the buildup of soot is burned off.
What to Do
This problem is usually temporary and solves itself, but you may need to intervene at times. Check for loose connections, inspect the sensors, and if everything looks fine, run your Volkswagen at highway speeds for approximately 30 minutes.
If the problem persists, take your car to certified Volkswagen mechanic for further diagnostics.
Note that if you’ve modified your Volkswagen with a cold air intake or aftermarket exhaust, it may trigger this code. If this applies to you, put the stock parts back on the car to see if the code will then go away.