What are the common causes of P2001?

A NOx adsorber on bank 2 that no longer stores NOx. An exhaust leak at the bank 2 adsorber. A degraded catalyst ahead of the bank 2 adsorber. A faulty NOx sensor on bank 2.

Read NOx and oxygen sensor data on bank 2. Inspect bank 2 exhaust for leaks. Check the bank 2 temperature sensor readings. Test the NOx sensor on bank 2. Replace the bank 2 NOx adsorber if efficiency stays low. Clear the code and retest.

P2001

NOx Adsorber Efficiency Below Threshold Bank 2

System: Fuel and air metering (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P2001 means NOx Adsorber Efficiency Below Threshold Bank 2.

Check these first

A NOx adsorber on bank 2 that no longer stores NOx
An exhaust leak at the bank 2 adsorber
A degraded catalyst ahead of the bank 2 adsorber
A faulty NOx sensor on bank 2

What to do next

Read NOx and oxygen sensor data on bank 2
Inspect bank 2 exhaust for leaks
Check the bank 2 temperature sensor readings
Test the NOx sensor on bank 2
Replace the bank 2 NOx adsorber if efficiency stays low
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.