P2000

NOx Adsorber Efficiency Below Threshold Bank 1

Emissions control (NOx) Generic OBD-II Low

What it means

P2000 means the NOx adsorber (NOx trap) on bank 1 is no longer storing and reducing nitrogen-oxide emissions as effectively as it should. The engine still runs and drives normally — this is an emissions efficiency fault. It's often a degraded trap or a faulty NOx sensor, and it will cause an emissions-test failure until corrected.

Low

Can I keep driving? Yes — the car drives normally. This is an emissions efficiency code; it won't strand you but it will fail an emissions test and may trigger a diesel regen or derate over time.

Real-world scan data

Seen in

999

scans in the past year

Found in

0.2%

of scans

0.3%

of scans that found faults

Appears alongside · share of P2000 scans

P0645in 13.4% of scans

P2003in 10.3% of scans

P24C7in 8.6% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Often no noticeable change in how the car drives
Possible increase in exhaust emissions
May fail an emissions/smog test

Common causes

Most likely first

Aged or degraded NOx adsorber (trap) with reduced storage capacityLikely
Faulty NOx sensor giving inaccurate readingsCommon
NOx sensor harness open, shorted, or with a poor connectionCommon
Exhaust leak upstream of the NOx trap or sensorLess often
Incomplete diesel regeneration cyclesLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data and scan for related NOx sensor or emissions codes.
Inspect the NOx sensor wiring and connectors for damage, corrosion, or looseness; repair as needed.
Check the exhaust for leaks between the engine and the trap/sensor.
Test the NOx sensor's readings against live data; replace the sensor if faulty.
If sensors and wiring are good, the NOx trap itself is likely degraded and may need replacement. Clear and re-run the drive cycle.

FAQ

Quick answers

Is it safe to drive with P2000?+

Yes, it's safe to drive. The concern is emissions, not reliability — but address it before an emissions test, and don't ignore it on a diesel that may derate.

Can I just clear P2000?+

You can clear it, but if the trap or sensor is genuinely failing the code returns after the monitor re-runs. It only stays gone once the underlying fault is fixed.

Read & clear P2000 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX