P2002 – Diesel particulate filter efficiency below threshold

The P2002 code applies to diesel engines. They contain an additional filter to remove soot and contaminants from the exhaust. This limits harmful emissions and allows your vehicle to meet state standards. 

The activation of P2002 indicates the inefficient filtering of your exhaust. This problem can be intermittent, and in some cases, will go away on its own with no driver intervention. You shouldn’t ignore it if it does stick around, though, as this affects both the environment and your engine’s performance.

Certain driving conditions and vehicles are more likely to activate the P2002 trouble code than others. Read on below to learn what you should do if this code triggers in your car or truck.

P2002 Code Definition (Generic): Diesel Particulate Filter Efficiency Below Threshold Bank 1

What does P2002 mean?

This code relates to diesel engines made in 2007 and later. These vehicles use an emission control device to lower the soot content of the exhaust. It does this by heating the engine enough to burn off pollutants, with an additional reductant catalyst to start the process.

The diesel particulate filter (DPF) removes about 98% of the soot in the exhaust when functioning correctly. If the emission control system has been activated, but the particulates in the exhaust don’t burn off, the P2002 trouble code activates. 

When the DPF is in operation, it generates backpressure. Pressure feedback sensors allow the engine control module (ECM) or powertrain control module (PCM) to monitor its operation. A discrepancy in the pressure limits indicates there’s an issue with the filter.

While this code is a generic powertrain code, applicable to any diesel engine, the specific fixes can vary depending on your make and model. P2002 is most common in Dodge, Chevy, Ford, and GMC pickups. It can also trigger diesel cars, such as those made by Audi, Lexus, and VW. 

This code is similar to P2003. The difference is P2002 relates to bank 1 of your engine, while P2003 points to bank 2. Bank 1 is the side of the engine that contains cylinder 1. 

P2002 is what is considered a “soft code.” This means it reports an issue in real-time and can clear itself if the fault is corrected. If this happens once, you don’t need to worry about it. Repeated instances of P2002 warrant diagnosis. You should also consider repairs if the code does not turn itself off after a completed drive cycle.

Here's where you can get a thorough understanding of the P2002 OBD2 code
If you want to learn about the P2002 OBD2 code, this is the right place

What are the symptoms of the P2002 code?

The check engine light may stay illuminated with P2002, or it may come on intermittently. In many cases, there are no drivability issues associated with this code. If there are symptoms, they include:

  • The activation of the check engine light
  • Reduced fuel economy
  • Sluggish acceleration
  • Diluted oil

What are the causes of P2002?

  • Fouled or faulty DPF.
  • The exhaust back pressure sensor is faulty.
  • Leaks in the exhaust system.
  • Fuel quality is too low for the engine.
  • The engine is not reaching high enough speeds/temperatures.
  • Aftermarket components are not suitable for vehicles.
  • The air cleaner element is dirty.
  • Faulty PCM/ECM or components.

How serious is the P2002 code?

The P2002 trouble code is moderately severe. Although you may not experience drivability issues, your engine may go into failsafe mode if you don’t clear the code. Because of this, it’s essential to find the source of the issue as soon as possible.

How to diagnose and fix the P2002 code

Tools you’ll need: OBD2 scan tool

  1. Use an OBD2 scan tool to read the codes. If other codes are present, fix those first.
  2. If you mostly drive in a city or at low speeds, your engine may not be reaching high enough temperatures to burn off the soot. Take your car for a hard drive. Ensure you get at least 55 miles per hour for 20-30 minutes, then reduce speed quickly. Clear the codes and rescan with the OBD2 scan tool.
  3. If you have recently modified your vehicle, replace it with the original part. Certain modifications, including cat-back exhaust kits or cold air intake kits, can trigger this code. You can also check with the manufacturer to see if this is a known issue for your vehicle. 
  4. Check for loose connections around the bank 1 DPF. Also, check for any burnt or loose wires, and make sure there’s no corrosion on the connectors.
  5. Look for exhaust leaks around the DPF. Pay close attention to the ends and connections, making sure everything is connected securely. 
  6. Verify that you’re using fuel that is the correct quality for your engine. The fuel that contains too much sulfur leads to clogs in the DPF. Consult your manual if you’re not sure what the ideal diesel quality is for your engine.
  7. Check the DPF for dirt and clogs. In some cases, these filters may become too fouled to clear with a hard drive. Replace the filter, then clear the codes and test drive your vehicle.
  8. Should the code still not clear, take your car to a mechanic for further diagnosis. Advanced scan tools like the Tech II can determine if there is an issue with the ECM or PCM.
The way to fix the p2002 code

Common mistakes to avoid while diagnosing the P2002 code

If the issue causing the P2002 trouble code is a fouled filter, it may be a temporary problem. Make sure you take a test drive, reaching at least 55 miles per hour before replacing any components. DPF filters generally last a long time, so don’t assume the filter is failing until you’ve checked for other issues. 

Tips to avoid P2002 in the future

Wires touching the DPF can be burnt and damaged by the high temperatures generated. Ensure all of the wires for the sensor are positioned away from engine components that could damage them. 

If you drive mostly at low speeds, P2002 could be a recurring problem. You may want to consider taking your vehicle to a mechanic for a modification. They can reprogram the computer and remove the PDF, solving the issue.

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