P2003: Diesel Particulate Filter Efficiency Below Threshold (Bank 2)
The particulate filter on bank 2 does not trap enough soot.
Normal risk
Safe to drive. Emissions are higher.
Short answer · Can I keep driving with P2003?
Yes. The car usually drives normally, but more soot leaves the exhaust. Have the filter and its pressure sensor checked soon.
What does P2003 mean?
Code P2003 is the bank 2 version of P2002. Only engines with two particulate filters, one per exhaust bank, can set it. The control unit sees too little pressure difference across the filter for the soot it expects, which points to a cracked or removed filter, or to a leak or fault in the pressure sensor hoses.
What the car does when the code is set
The particulate filter or check engine light comes on. The car usually drives normally, but emissions of soot are higher. On some cars regeneration is suspended.
How the system works
A diesel particulate filter traps soot from the exhaust in a ceramic honeycomb with closed channels. The soot is burnt off at intervals by raising the exhaust temperature, a process called regeneration. A differential pressure sensor measures the pressure before and after the filter: a full filter gives a high difference, a damaged or empty filter almost none. If the pressure difference is too low for the exhaust flow, the engine control unit concludes the filter is no longer working.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Damaged or cracked particulate filterThe filter no longer traps soot.
- Removed or tampered filterAn emptied filter is detected.
- Faulty differential pressure sensorThe sensor misreads the pressure across the filter.
- Leaking sensor hosesSplit hoses to the pressure sensor.
How it is diagnosed
- Check the sensor hosesInspect the hoses from the filter to the pressure sensor for splits and correct connection.
- Check the pressure readingWith the engine off, the differential pressure should read near zero.
- Look for soot at the tailpipeBlack soot inside the tailpipe after a clean suggests a damaged filter.
- Have the filter inspectedA workshop checks the filter for cracks.
Questions about P2003
Why bank 2?
Some V engines have a separate exhaust and particulate filter for each cylinder bank. Bank 2 is the side without cylinder 1.
Is removing the particulate filter allowed?
No. Removing the filter is illegal for road use in most countries and fails inspections.
Can a pressure sensor fault cause this code?
Yes. Always check the sensor and hoses before replacing the filter.