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P2001 Emissions / Exhaust
NOx Trap Efficiency Below Threshold Bank 2
P2001 is the Bank 2 version of the NOx trap efficiency fault. The NOx trap on Bank 2 is not storing and reducing nitrogen oxides efficiently. Causes include an aged trap, a NOx sensor fault, or a failed regeneration cycle.
🚗 Yes, but the vehicle will not meet emissions standards and the trap should be serviced.
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🎯 Top Causes, Ranked by Likelihood
#1 Aged or saturated NOx trap/catalyst $500-$2000
The Bank 2 trap has lost storage capacity.
#2 Faulty NOx sensor $200-$600
A bad sensor gives incorrect efficiency readings.
#3 Failed regeneration or fuel dosing issue $100-$800
The trap cannot regenerate to clear stored NOx.
#4 Exhaust leak or restricted flow $100-$600
Leaks upset the NOx measurement.
🩺 Common Symptoms Check engine light on Possible reduced power or limp mode Increased emissions Will fail an emissions test 💰 Repair Cost: DIY vs Shop
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🔧 How to Diagnose P2001 1 Scan for related NOx and regeneration codes
2 Check Bank 2 NOx sensor readings
3 Inspect the exhaust for leaks and restrictions
4 Verify regeneration completes and dosing works
❓ Frequently Asked Questions Can I drive with a P2001 code?
Usually yes short-term, but some vehicles limit power. The car will not pass emissions, so repair it soon.
How much does it cost to fix P2001?
A NOx sensor may be $200 to $600, while a new trap can exceed $1000 at a shop.
What is the most common cause of P2001?
An aged or saturated NOx trap on Bank 2 is the most common cause.
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