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P2002 OBD-II Trouble Code: Diesel Particulate Filter Efficiency Below Threshold Bank 1

diagnostic check engine light

P2002 definition

A P2002 trouble code is related to a diesel vehicle’s particulate filter that helps eliminate the dark soot that will naturally want to come out of the tailpipe.

What the P2002 code means

P2002 is a SAE controlled, diesel-specific OBD-II generic code for an efficiency issue with the particulate filter that is located on the exhaust. If the signal from the back pressure sensor being sent to the engine computer is not within the manufacturer’s parameters, the computer will deem the filter to be faulty, triggering the code. Bank 1 designates the filter that is responsible for the bank of cylinders that includes cylinder one.

What causes the P2002 code?

The most common causes for a P2002 are:

  • Faulty particulate filter
  • Faulty exhaust back pressure sensor
  • Exhaust leak
  • Poor quality diesel fuel

What are the symptoms of the P2002 code?

Because diesel particulate filters serve an emissions purpose, most P2002 codes won’t result in more than a check engine light or a DPF Warning Light. In some cases, poor engine performance and decreased fuel economy will result, and some vehicles may exhibit excessive visual emissions i.e. black soot.

How does a mechanic diagnose the P2002 code?

When dealing with a P2002, a visual inspection of both the particulate filter and the back pressure sensor and associated wiring will come first. After this, your mechanic will typically test drive the vehicle with an OBD-II scanner connected to track the back pressure sensor readings. If bank 1 appears to be sending different signals than bank 2, further troubleshooting of the sensor may be needed before determining the particulate filter should be replaced.

Common mistakes when diagnosing the P2002 code

Poor quality fuel can often temporarily foul a diesel particulate filter. This is why a test drive at highways speeds is important to try and clear out the filter before replacing parts.

How serious is the P2002 code?

Leaving a P2002 on for an extended period of time can sometimes cause the engine computer to enter limp mode. This limits the top speed and reduced engine power to protect the internal components of the drivetrain.

What repairs can fix the P2002 code?

The most common repairs for a P2002 are as follows:

  • Clearing the diesel particulate filter
  • Changing the diesel fuel
  • Replacing the diesel particulate filter
  • Replacing the back pressure sensor

Additional comments for consideration regarding the P2002 code

Diesel particulate filters were not widely used until the mid-2000s, so if your diesel vehicle is older, it may not encounter a P2002.

Need help with a P2002 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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