P2000 - NOx Adsorption Catalyst Efficiency Below Threshold (Bank 1)
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System
Powertrain (Engine & Gearbox)
OBS!This code is in a manufacturer-specific range. The description may vary depending on the vehicle manufacturer.
Related Fault Codes
Technical Description
P2000 is a generic diagnostic trouble code (DTC) indicating that the NOx trap (Lean NOx Trap/Adsorption Catalyst) on Bank 1 is underperforming. The PCM (Powertrain Control Module) monitors the efficiency of the catalyst using NOx sensors. When the adsorption capacity of the catalyst reaches its limit or fails to reduce NOx levels during a regeneration event (rich-cycle), the threshold is breached. This diagnosis is part of the OBD-II emission control strategy and aims to ensure nitrogen oxide emissions remain within regulated limits.
Possible Causes
Failed NOx trap (catalyst aging or poisoning)
Faulty NOx sensor (Bank 1)
Exhaust leak upstream of the NOx trap (disturbs reading with oxygen)
Faulty fuel injection or intake air leak (preventing proper regeneration chemistry)
Sulfur contamination of the catalyst (use of high-sulfur fuel)
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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