NOx Trap Efficiency Below Threshold (Bank 2)
The P2001 code means the vehicle's onboard diagnostic system has detected: NOx Trap Efficiency Below Threshold (Bank 2). This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $800 - $2,500 (parts and labor)
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Common Symptoms
- Check Engine Light illuminated
- Reduced engine power on Bank 2 cylinders
- Sulfur smell from exhaust
- Higher than normal exhaust emissions
- Failed emissions inspection
Probable Causes (Ranked by Likelihood)
- Degraded NOx trap catalyst on Bank 2 Very High
- Sulfur poisoning from fuel High
- Faulty downstream NOx sensor Moderate
- Exhaust leak near Bank 2 NOx trap Moderate
- PCM calibration issue Low
Step-by-Step Diagnostic Procedure
-
Read freeze frame data and confirm P2001 is present
-
Compare Bank 1 and Bank 2 NOx sensor readings
-
Inspect Bank 2 NOx trap for contamination or damage
-
Check for exhaust leaks on the Bank 2 side
Frequently Asked Questions
What does P2001 mean?
P2001 means the NOx trap catalyst on Bank 2 has fallen below its efficiency threshold, indicating it can no longer adequately reduce nitrogen oxide emissions.
Can I drive with a P2001 code?
Short-distance driving is possible, but expect reduced power and failed emissions tests. Prolonged driving risks further catalyst damage.
How much does it cost to fix P2001?
Expect $800 to $2,500 depending on whether the NOx trap needs replacement or if a sensor is the root cause.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P2001 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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