OBD-II code family
NOx Sensor Circuit and Heater Faults (39 codes)
39 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P2200NOx Sensor Circuit (Bank 1)
- P2201NOx Sensor Circuit Range/Performance (Bank 1)
- P2202NOx Sensor Circuit Low (Bank 1)
- P2203NOx Sensor Circuit High (Bank 1)
- P2204NOx Sensor Circuit Intermittent (Bank 1)
- P2205NOx Sensor Heater Control Circuit/Open (Bank 1)
- P2206NOx Sensor Heater Control Circuit Low (Bank 1)
- P2207NOx Sensor Heater Control Circuit High (Bank 1)
- P2208NOx Sensor Heater Sense Circuit (Bank 1)
- P2209NOx Sensor Heater Sense Circuit Range/Performance (Bank 1)
- P2210NOx Sensor Heater Sense Circuit Low (Bank 1)
- P2211NOx Sensor Heater Sense Circuit High (Bank 1)
- P2212NOx Sensor Heater Sense Circuit Intermittent (Bank 1)
- P2213NOx Sensor Circuit (Bank 2)
- P2214NOx Sensor Circuit Range/Performance (Bank 2)
- P2215NOx Sensor Circuit Low (Bank 2)
- P2216NOx Sensor Circuit High (Bank 2)
- P2217NOx Sensor Circuit Intermittent (Bank 2)
- P2218NOx Sensor Heater Control Circuit/Open (Bank 2)
- P2219NOx Sensor Heater Control Circuit Low (Bank 2)
- P2220NOx Sensor Heater Control Circuit High (Bank 2)
- P2221NOx Sensor Heater Sense Circuit (Bank 2)
- P2222NOx Sensor Heater Sense Circuit Range/Performance (Bank 2)
- P2223NOx Sensor Heater Sense Circuit Low (Bank 2)
- P2224NOx Sensor Heater Sense Circuit High (Bank 2)
- P2225NOx Sensor Heater Sense Circuit Intermittent (Bank 2)
- P229ENOx Sensor Circuit (Bank 1 Sensor 2)
- P229FNOx Sensor Circuit Range/Performance (Bank 1 Sensor 2)
- P22A0NOx Sensor Circuit Low (Bank 1 Sensor 2)
- P22A1NOx Sensor Circuit High (Bank 1 Sensor 2)
- P22A2NOx Sensor Circuit Intermittent (Bank 1 Sensor 2)
- P22A3NOx Sensor Heater Control Circuit/Open (Bank 1 Sensor 2)
- P22A4NOx Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
- P22A5NOx Sensor Heater Control Circuit High (Bank 1 Sensor 2)
- P22A6NOx Sensor Heater Sense Circuit (Bank 1 Sensor 2)
- P22A7NOx Sensor Heater Sense Circuit Range/Performance (Bank 1 Sensor 2)
- P22A8NOx Sensor Heater Sense Circuit Low (Bank 1 Sensor 2)
- P22A9NOx Sensor Heater Sense Circuit High (Bank 1 Sensor 2)
- P22AANOx Sensor Heater Sense Circuit Intermittent (Bank 1 Sensor 2)
What these codes mean
These thirty-nine entries compare three named groups: Bank 1 P2200–P2212, Bank 2 P2213–P2225, and Bank 1 Sensor 2 P229E/P229F/P22A0–P22AA. Each group separates five sensor-circuit conditions, three heater-control conditions and five heater-sense conditions. Keep the full code, suffix and status: circuit/open, range/performance, low, high and intermittent are different reports, not instructions to replace a sensor.
Match the bank and sensor address to the actual installation. Bank 2 does not automatically mean Sensor 2, and Sensor 2 does not establish a universal downstream location, connector or interchangeable part. GM’s 2021 Tahoe 2WD service entry describes calibrated NOx Sensor 2 electronics supplying lambda and NOx information over serial data. Volvo/Mack’s cited article distinguishes smart inlet and outlet identities. Identify the assembly and reporting controller before choosing tests or parts.
A circuit label is not always a direct voltage or gas-concentration reading. The 2014 Touareg CNRB tables use P229E status/message-validity and feedback checks, P229F offset, self-diagnostic and response checks, and P22A0/P22A1 NOx/lambda range categories. Ford’s covered 2023–2024 diesel summary instead calls P229E a processor-performance report. Use the actual monitored function; neither example turns every circuit fault into a lost network message or certifies all electrical paths after a performance result.
Keep the general Sensor 2 circuit group P229E/P229F/P22A0/P22A1/P22A2 separate from heater control P22A3/P22A4/P22A5 and heater sense P22A6/P22A7/P22A8/P22A9/P22AA. A low or high circuit classification does not by itself establish unusually clean exhaust, excessive NOx, ammonia slip or catalyst failure. An intermittent label does not identify a weather-related connector, an exhaust mount or one predictable point of wire damage.
Heater control and feedback also need different interpretation. A sense fault does not prove the heater works, and a control fault does not identify one switching polarity or shared DEF-heater supply. Ford’s cited tailpipe NOx/O2 section calls P22A7 signal readiness and lists separate heater checks under P220F. GM’s cited 2021 entry uses heater-feedback wording and its own prerequisites. Do not substitute a generic cold-start timer, warm-up drive or reassuring continuity reading for the applicable monitor.
Complete suffixes and diagnostic status can change the next step. The dated Volvo/Mack US10+OBD13-and-newer article places outlet P229E-13/P22A1-00 and P22A3-13/P22A4-00/P22A6-00 in a status-dependent sensor-failure branch, while P229F-64 has a different diagnostic disposition. Preserve active, confirmed and inactive distinctions. This application example does not make every occurrence of the same five-character code a sensor-replacement instruction.
Software is another conditional example. GM 24-NA-094, April 2025 Version 2, lists several of these NOx reports for specified 2024 Silverado 1500/Sierra 1500 3.0L applications. Its direction depends on an applicable calibration; ordinary service diagnosis applies when no new calibration is available. Match the vehicle, condition and current instructions. A listed software case does not establish that an update is available for this vehicle or that its hardware is healthy.
Preserve the full scan, event data, companion faults and actual warning messages. Have the prescribed protected electrical, communication, component and software checks performed with the required cooling and isolation. Do not directly power a heater, bridge unknown pins, apply heat or water to live connections, interchange sensors or drive to provoke a complaint. Confirm the repair, setup and relevant monitor rather than judging one cleared code or plausible value.
Follow the vehicle’s actual warnings and operating behavior. This group does not establish a fixed power restriction, restart countdown or safe mileage allowance. A useful quote identifies the demonstrated cause, actual part or harness section, labor and any required setup or software work; age, bank number and companion codes alone do not approve a pair of sensors or a controller.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.