P2003: Particulate Filter Efficiency Below Threshold — Bank 2
What to do
As with P2002 — ask for a forced regeneration and the pressure reading afterwards before accepting a replacement. If only one bank is affected, that points at something specific to those cylinders rather than at how the car is driven.
What this code means
The same conclusion as P2002 on bank 2, found on engines carrying a filter per bank. The full argument about regeneration, ash and upstream causes is set out under P2002 and applies unchanged.
What the bank pairing adds: both banks reporting together points at driving pattern, fuel or a regeneration strategy that is not completing, since those affect the whole exhaust equally. One bank alone is more likely a sensor on that side, or an engine fault producing soot on those cylinders only — a leaking injector, for instance, is a per-cylinder fault and shows on one bank.
Likely causes
Start here
- Predominantly short journeys · easy
- Incomplete particulate filter regeneration · moderate
- Faulty exhaust gas differential pressure sensor · moderate
- Leaking fuel injector · moderate
Less common
- Ash loading at end of filter life · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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