P2201: NOx Sensor Circuit Range/Performance (Bank 1)
3 vehicles · 3 makes · $300-$3,500 repair
Most Reported On
P2201 is an OBD-II diagnostic trouble code meaning “NOx Sensor Circuit Range/Performance (Bank 1).” This code means the engine computer detected that the NOx (nitrogen oxides) sensor signal on Bank 1 is out of its expected range or not performing correctly. The NOx sensor measures nitrogen oxide levels in the exhaust, mainly on diesel and lean-burn engines, to manage the emissions/SCR system. An implausible reading means the computer can't accurately monitor or control emissions. While not an immediate driving hazard, it can cause emissions faults, failed inspections, and in some vehicles reduced-power modes if the system can't verify proper operation. This code is most commonly reported on 2013-2025 RAM 2500 (Big Horn, Laramie, Laramie Longhorn, Limited, Limited Longhorn, Lone Star, Rebel, SLT, Tradesman), 2018-2023 Ford Transit, and 2011-2016 Mercedes-Benz E-Class (E250 BlueTEC, E250 BlueTEC 4MATIC, E350 BlueTEC), with repair costs ranging from $300 to $3,500.
Common Causes
Typical Repair Cost
Based on 3 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P2201.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (3)
FAQ
What does P2201 mean?
P2201 stands for "NOx Sensor Circuit Range/Performance (Bank 1)." This code means the engine computer detected that the NOx (nitrogen oxides) sensor signal on Bank 1 is out of its expected range or not performing correctly. The NOx sensor measures nitrogen oxide levels in the exhaust, mainly on diesel and lean-burn engines, to manage the emissions/SCR system. An implausible reading means the computer can't accurately monitor or control emissions. While not an immediate driving hazard, it can cause emissions faults, failed inspections, and in some vehicles reduced-power modes if the system can't verify proper operation.
What are the most common causes of P2201?
The most common causes of P2201 are: Faulty NOx sensor, Wiring or connector problems at the NOx sensor, Exhaust leak near the sensor affecting readings, Contaminated or aged sensor element, DEF/SCR system performance issues skewing readings, NOx sensor control module fault. The specific cause varies by vehicle.
How much does it cost to fix P2201?
Repair costs for P2201 range from $300 to $3,500, depending on the vehicle and root cause.
Which vehicles are affected by P2201?
Au7o has documented P2201 across 3 vehicle models from 3 manufacturers: Ford, Mercedes-Benz, RAM.
Sources (10)
- ForumCummins Forum: SCR gone bad
- ForumRamForumz: DEF issue
- mediaTruck Camper Adventure: Going Into the Dreaded Diesel DEF Limp Mode
- manufacturerBSBuilt: Maintain 6.7L Cummins DEF System (2010-2025)
- ForumRamForumz: P2048 5 MPH Derate Def system problem
- NHTSANHTSA Manufacturer Communications Data Corpus
- ForumReplace NOx sensor or delete AdBlue? - MBWorld.org Forums
- ForumContinous problem with Adblue - MBWorld.org Forums
- ForumAdBlue warning Engine start countdown | Mercedes-Benz Forum (BenzWorld)
- ForumNOX Sensor Fault - linked to Adblue fault and countdown? | Mercedes-Benz Owners' Forums
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.