P2000 code meaning
NOx Adsorber Efficiency Below Threshold (Bank 1)
Powertrain system Generic code P20xx codes Check engine light
What P2000 means
A NOx adsorber (lean NOx trap) collects nitrogen oxides while a lean-running engine produces them and turns them into nitrogen during short rich purges. P2000 reports that the trap on bank 1 no longer stores or converts enough NOx; CARB wants this flagged before tailpipe NOx passes a fixed multiple of the standard. Chrysler documents the code on 2007 to 2011 Ram 2500/3500 pickups with the 6.7 L Cummins: bulletin 25-001-13 links it, often together with P2A00/P2A01, to sooted oxygen sensors has both sensors cleaned or replaced and a heat shield added, while 18-012-12 brings revised engine software for P2000 and other codes on the 2011 trucks. Sulphur poisoning, thermal ageing or purges that never complete are further reasons. The truck usually drives normally, but NOx output rises.
P2000 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P2000
- Malfunction indicator lamp on
- Often accompanied by oxygen sensor codes P2A00/P2A01
- No noticeable change in driveability
Common causes of P2000
- Most likelySooted or drifting oxygen sensors that misjudge trap loading and purges
- PossibleNOx trap poisoned by sulphur or aged by heat
- PossibleEngine software that sets the code without a real fault (update available on some models)
- Less likelyRich purges or desulphation not completed, e.g. because of short trips
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Nox adsorber catalystNox sensor downstreamExhaust temperature sensor
What each part of P2000 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 00 | The exact fault in that area. |
What to do next
- Note P2000 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2000
What does P2000 mean?
P2000 means "NOx Adsorber Efficiency Below Threshold (Bank 1)". A NOx adsorber (lean NOx trap) collects nitrogen oxides while a lean-running engine produces them and turns them into nitrogen during short rich purges. It is a generic code, so it means the same on every make.
Is it safe to drive with P2000?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2000 fail an emissions test?
Yes, it can. P2000 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2000 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P2000 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.