P2000: NOx Adsorber Efficiency Below Threshold (Bank 1)
Quick Answer
Safe to drive (short-term)
P2000 means the engine computer has tested the NOx trap (also called a NOx adsorber, NOx storage catalyst or lean NOx trap) on bank 1 and found it is removing less nitrogen oxide than it should. A NOx trap is a catalyst fitted to some diesels and a few lean-burn petrol engines: it stores NOx during normal running, and the engine then runs briefly rich to release the stored NOx and turn it into nitrogen. A trap is not an SCR system: it needs no AdBlue, while an SCR system does and is usually judged by its own efficiency code, P20EE (VW group documentation also lists reductant dosing under P2000). The usual causes are an aged or fuel-contaminated trap, a faulty sensor that judges the trap, an exhaust leak or poor fuel. P2001 is the bank 2 twin, which only exists on engines with two banks.
- Severity
- Moderate · Emissions
- Estimated repair cost
- From €65 to €3000+, varies by vehicle
€65 or €3000, depending on your car.
- Replace exhaust gas temperature sensor€65–€220
- Replace NOx trap (NOx storage catalyst); wide range, no firm price exists€650–€3000
A scan shows whether P2000 is really stored on your car, which codes sit next to it and how urgent each one is.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P2000 mean?
P2000 is a emissions-related diagnostic trouble code classified as moderate severity.
What are the symptoms of P2000?
- Check engine light on
- Often no change in how the car drives
- Reduced power or limp mode on some cars
- Higher fuel use if the trap is regenerating more often
- Higher NOx emissions, which can fail an emissions check
- NOx sensor, oxygen sensor or exhaust temperature sensor codes stored at the same time
What causes P2000?
NOx trap that is worn, aged or contaminated with fuel sulphur and can no longer store enough NOx
: high
Faulty or slow NOx sensor or oxygen sensor before or after the trap, giving the computer a wrong picture of the trap
: high
Exhaust leak upstream of the trap or around it
: medium
Faulty or slow exhaust gas temperature sensor, so the trap is not regenerated at the right temperature
: medium
Poor-quality fuel or fuel with the wrong sulphur content
: medium
Engine fault that changes the exhaust the trap sees: leaking injector or EGR problem
: low
On a car with an SCR system and an AdBlue tank: an AdBlue dosing fault, which some makes list under this code too
: low
Is it safe to drive with P2000?
Generally yes, for short-term driving. You can usually keep driving. The trap is an emissions part, so the main effects are higher nitrogen oxide emissions and a car that can fail an emissions check, and some cars also drop into reduced power. Have it checked within a few weeks, because the cause is often a sensor or an exhaust leak that is cheaper to fix early, and if the car goes into limp mode or a warning light flashes, stop sooner.
How do you diagnose P2000?
- Find out what the car has. A filler cap for AdBlue means the car has an SCR system, which most makes judge with P20EE, although VW group lists dosing faults under P2000 as well, so on those cars the code can involve the SCR side. A diesel with no AdBlue tank has a NOx trap. Then read all stored codes and the freeze frame. A generic OBD2 reader shows the codes, the freeze frame and standard live data, but on most cars not the NOx readings, the trap's load or its regeneration status, and it cannot start a trap regeneration or the manufacturer's clean-out routine: those need manufacturer-level software.
- Deal with any sensor codes stored alongside first: NOx sensor circuit codes such as P2200, oxygen sensor codes and exhaust temperature sensor codes. The computer judges the trap from these sensors, so a faulty one can make a good trap look worn.
- Look over the exhaust from the engine to the trap for leaks, cracks and loose joints, and check the sensor connectors for corrosion and heat damage. A leak changes the oxygen the sensors see.
- Ask about recent fuel. Sulphur from poor or wrong-grade fuel takes up the places where the trap stores NOx. Some makes have a high-temperature clean-out routine for this, run with manufacturer-level software, but whether yours does is a question for the workshop data.
- With manufacturer-level software, compare the NOx or oxygen readings before and after the trap during a regeneration, and check the trap's temperature. A downstream reading that does not fall well below the upstream one during regeneration points to the trap itself.
- Check the engine for faults that spoil the exhaust, such as a leaking injector or an EGR fault, and fix them before condemning the trap. A new trap fitted to an engine that still produces the same exhaust will wear out the same way.
- After the repair, clear the code and have any trap or sensor adaptations done that the manufacturer asks for. The efficiency monitor runs only in certain conditions, so confirm the repair over several normal trips.
How much does P2000 cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Repair exhaust leak before or around the trap | €20–€100 | €60–€200 | €80–€300 | Professional |
| Replace oxygen (lambda) sensor before or after the trap | €60–€250 | €40–€150 | €100–€400 | Moderate |
| Replace exhaust gas temperature sensor | €25–€100 | €40–€120 | €65–€220 | Moderate |
| Replace NOx sensor (on cars that use them to judge the trap) | €250–€1000 | €100–€300 | €350–€1300 | Professional |
| Replace NOx trap (NOx storage catalyst); wide range, no firm price exists | €500–€2500 | €150–€500 | €650–€3000 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
P2000 on specific vehicles
P2000 on Honda
Honda Civic 1.6 i-DTEC
P2000 on Mazda
Mazda CX-3 1.8 SKYACTIV-D
P2000 on Volkswagen
Volkswagen Golf 2.0 TDI (EA288)
Related diagnostic codes
Common questions about P2000
- What does P2000 mean?
- P2000 means the engine computer has found that the NOx trap on bank 1 is not removing enough nitrogen oxide. The trap stores NOx while the engine runs normally and clears it during short rich phases, and the computer checks how well that works using sensors before and after the trap. The code does not say whether the trap, a sensor or an exhaust leak is at fault, which is why the cause has to be traced.
- Is a NOx trap the same as AdBlue or SCR?
- No. A NOx trap stores nitrogen oxides and clears them with brief rich engine running, so it needs no fluid. An SCR system injects AdBlue into the exhaust to break the NOx down, and most makes judge it with P20EE, though VW group documentation also lists reductant dosing faults under P2000. Some engine families use one or the other depending on the model: the Euro 6 versions of the VW EA288 diesel, for example, are described as having either a NOx storage catalyst or an SCR system. Check for an AdBlue filler cap before deciding which one your car has.
- Can I drive with P2000?
- Usually yes, for a while. The car emits more NOx than it should and can fail an emissions check, and on some cars power is reduced. It is not an emergency on its own, but get the cause found within weeks rather than months, because a leak or a bad sensor is cheaper to fix than a trap that has been left working badly.
- Can a long drive or new fuel clear P2000?
- Only if the cause was temporary, such as one tank of poor fuel, and even then the trap needs time and the right conditions to recover. If the code comes back within days, something else is wrong: a sensor, an exhaust leak or the trap itself. Clearing the code without finding the cause only delays it.
- How much does it cost to fix P2000?
- It depends on the cause. An exhaust leak repair costs about 80 to 300 EUR, an oxygen sensor 100 to 400 EUR and an exhaust temperature sensor 65 to 220 EUR fitted. A NOx sensor is 350 to 1,300 EUR. A replacement NOx trap is a wide and uncertain range, roughly 650 to 3,000 EUR, because the price depends heavily on the car and on whether the trap is a separate part.
- Can a cheap OBD2 reader diagnose P2000?
- It can read and clear the code and show the freeze frame, which tells you when the fault set. On most cars it cannot show the NOx readings or the trap's regeneration status, and it cannot start a regeneration or the manufacturer's clean-out routine. Those need manufacturer-level software, so a reader is a starting point, not a verdict.
Read our detailed guides
Sources
- carmag.co.za carmag.co.za/news/new-models/honda-details-frugal-new-i-dtec-engine-for-civic/
- fleetworld.co.uk fleetworld.co.uk/diesel-returns-to-the-honda-civic/
- autozine.nl autozine.nl/mazda/nieuws/complete-mazda-gamma-conform-euro-6dtemp
- fleetworld.co.uk fleetworld.co.uk/mazda-cx-3-updated-for-euro-6b/
- en.wikipedia.org en.wikipedia.org/wiki/Mazda_CX-3
- carwiki.de carwiki.de/vw-ea288-motor
- wiki.ross-tech.com wiki.ross-tech.com/wiki/index.php/18432/P2000/008192