P2201 on Chevrolet
NOx Sensor Circuit Range/Performance (Bank 1)
P2201 on Chevrolet vehicles indicates nox sensor circuit range/performance (bank 1). Au7o has documented this code across 1 Chevrolet model — most commonly on Silverado 2500HD. 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. Typical repair costs on Chevrolet range from $400 to $1,400, depending on the specific model and root cause.
Common Causes of P2201
- •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
P2201 on Chevrolet by Model
Chevrolet Silverado 2500HD(1 issue)
- LML Duramax NOx Sensor Drift - False 'DEF Quality Poor' Warning and Speed Limiter Countdown2011-2015
Early LML trucks (roughly 2011 through 2014) are documented for upstream and downstream NOx sensors that drift out of calibration rather than fail outright. The SCR system compares the two sensors to judge DEF effectiveness; when a sensor reads out of range the truck posts 'DEF Quality Poor' or 'Exhaust Fluid System - See Dealer' and begins a countdown that ultimately limits the truck to a 4 mph creep speed - with perfectly good DEF in the tank. Because the sensors drift in and out of range, the message often comes and goes, which is why owners replace sensors and see the light return. GM has published harness-chafe bulletins covering the same fault codes, so the wiring is a genuine root cause and not just a sensor problem.
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View P2201 across all makes →Frequently Asked Questions
What does P2201 mean on Chevrolet?▼
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. On Chevrolet specifically, this code is documented across 1 model.
What causes P2201 on Chevrolet vehicles?▼
Common causes on Chevrolet: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2201 on a Chevrolet?▼
Repair costs on Chevrolet range from $400 to $1,400, depending on the specific model and root cause.
Which Chevrolet models have P2201 documented?▼
Au7o has documented P2201 on 1 Chevrolet model: Silverado 2500HD.