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P2003 OBD-II Trouble Code: Diesel Particulate Filter Efficiency Below Threshold Bank 2

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P2003 trouble code definition

P2003 is a generic diagnostic trouble code (DTC) that indicates a fault with the Diesel particulate filter.

This code is identical to the P2002 code except that P2002 is for bank 1.

What the P2003 code means

The P2003 code means that the diesel particulate filter efficiency has dropped below the given threshold for bank 2. The ECU closely monitors the diesel particulate filter and its efficiency and when it drops below the expected range a Check Engine Light is set. The Check Engine Light will be displayed on the dashboard and will remain until repaired or normal operation is present. P2003 may cause a limp mode if left unattended.

What causes the P2003 code?

  • Faulty, damaged, or clogged DPF filter
  • Exhaust pressure sensor has failed
  • Driving at low speeds for a long period of time
  • Excessively high sulfur content in the fuel

What are the symptoms of the P2003 code?

  • Check Engine Light being present
  • Limited speed and engine performance if limp mode is enabled
  • Poor fuel economy

How does a mechanic diagnose the P2003 code?

  • Qualified technicians will begin by using a scan tool to access all codes stored in the ECU.

  • Technicians will note codes present and any freeze frame data associated with them.

  • Next all codes will be cleared.

  • A long test drive at freeway speeds is done in order to burn out any particulate found in the DPF filter.

  • If the code reappears, then a visual inspection will be done looking for any damage to the DPF or wiring.

  • Next, the live engine data will be observed while the engine is operating and the throttle will be depressed looking for a change in the exhaust pressure sensor readings in comparison to bank 1.

Common mistakes when diagnosing the P2003 code

  • Mistakes are easy to make when diagnostic steps are not completed in the proper order.

  • A common mistake is to replace the DPF when it just needed to be driven at freeway speeds to clear the filter out.

How serious is the P2003 code?

If nothing is done to repair the persistent P2003 code, the ECU will put the vehicle into a limp mode. This mode limits the top speed and reduces engine power greatly to protect the engine. The limp mode can be problematic if far from home.

What repairs can fix the P2003 code?

  • Diesel particulate filter (DPF) replaced or unclogged
  • Exhaust pressure sensor replaced
  • Replacement of the fuel

Additional comments for consideration regarding the P2003 code

An advanced level scan tool will be helpful in diagnosing the P2003 code. These scan tools allow access to the the ECU’s data stream which shows live data such as sensor readings and voltage. With this information it makes it much easier to ensure many different systems are operating properly.

Need help with a P2003 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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