Emissions control: EGR, DPF, catalytic converter and AdBlueGeneric OBD-II codeUrgency: Garage soon
Code P2200: NOx sensor circuit (bank 1)
P2200 means: NOx (nitrogen oxides) sensor circuit, bank 1.[1][2] The engine ECU has detected a fault in the electrical circuit of the bank 1 NOx sensor, the sensor that measures the nitrogen oxides in the exhaust gases. On diesels with an SCR catalytic converter (the one that uses AdBlue) there are usually one before and one after the catalyst; according to HELLA, the rear one is used to check that the catalyst reduces NOx properly, and RACE describes them as sensors that measure that concentration before and after the catalyst.[1][2][3][4][5]
What code P2200 means
The engine ECU has detected a fault in the electrical circuit of the bank 1 NOx sensor, the sensor that measures the nitrogen oxides in the exhaust gases. On diesels with an SCR catalytic converter (the one that uses AdBlue) there are usually one before and one after the catalyst; according to HELLA, the rear one is used to check that the catalyst reduces NOx properly, and RACE describes them as sensors that measure that concentration before and after the catalyst.[1][2][3][4][5]
A NOx sensor is not a simple probe: according to HELLA it has its own control unit and an integrated heater that keeps it at around 300 °C, and it sends its data to the ECU over the data bus. That is why a "circuit" fault can come from the wiring, the power supply, the heater or the communication, and not only from the sensor itself.[3]
NOx sensors are fitted to cars that meet the Euro 5 and Euro 6 emissions standards (HELLA). Some sources attribute P2200 to the front sensor, the one before the SCR catalyst (FleetRabbit places it there), but the standard's definition only says "bank 1": it is best to check with the diagnostic tool which sensor it points to on each car.[2][3][6]
It is a generic OBD-II code (it starts with P2), so it means the same on any make; what changes from one engine to another is the most likely cause.[7]
Original definition (SAE J2012): NOx Sensor Circuit Bank 1[1][2]
Causes of P2200
From most to least likely, according to the sources.
- 1Faulty or contaminated NOx sensor: HELLA cites wear with age, fouling from short journeys or oil consumption, moisture, water and road salt, and AdBlue deposits from incorrect dosing; FleetRabbit adds poor-quality AdBlue, which poisons the ceramic element.[1][2][3][6]
- 2Damaged, chafed or corroded wiring or connectors, or a sensor power supply fault.[1][2][3][6]
- 3Faulty integrated sensor heater; as it is part of the sensor, FleetRabbit explains that it means the whole sensor has to be replaced.[6]
- 4Communication fault between the sensor and the ECU over the data bus: HELLA includes the power supply and the CAN communication among its checks.[3]
- 5Engine ECU with out-of-date software, or a faulty one.[1][2][6]
- 6Exhaust leaks near the sensor.[2]
Symptoms
- Engine warning light on in the instrument cluster.[1][3]Engine warning light: faults that cause it
- SCR (AdBlue) system warning in the instrument cluster.[3]AdBlue warning: faults that cause it
- The SCR system may go into emergency operation (HELLA); on heavy trucks, FleetRabbit describes a countdown after which power is limited.[3][6]Limp mode: faults that cause it
- Higher fuel consumption or poorer engine performance.[2][3]Uses more fuel: faults that cause it
How to diagnose P2200
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the fault memory with a diagnostic tool and see whether there are other SCR or NOx sensor codes. If there are faults on both the front and rear sensors, FleetRabbit recommends repairing the front one first, because its erroneous data can trigger false codes on the rear one and on the SCR catalyst.[3][6]
- 2Visually inspect the exhaust, the wiring and the sensor's connectors: melted, chafed or broken wires, corroded connectors and exhaust leaks near the sensor.[1][2][3]
- 3Look in the live data at the NOx values before and after the SCR catalyst, together with engine speed and SCR temperature. According to FleetRabbit, a front sensor that reads zero, sticks at maximum or does not respond to load is faulty, and a rear sensor that reads higher than the front one is impossible with a working SCR, so one of the two sensors is failing.[3][6]
- 4Use measuring equipment to check the sensor's power supply and the CAN bus communication, and consult the car's wiring diagram to see which terminal each wire corresponds to.[3]
- 5Ask a garage with access to the manufacturer's data whether there is an ECU software update for your engine: FleetRabbit lists it as a cause on trucks and CarWiki recommends checking that the software is up to date.[2][6]
- 6If the sensor's wiring or housing is damaged, HELLA says to replace the complete unit, without mixing up the front and rear ones, and then carry out the sensor adaptation with the diagnostic tool.[3]
Can I keep driving with P2200?
Garage soon
The sources do not give a uniform guideline. CarWiki speaks of moderate severity: you can drive, but it is not recommended without diagnosing it, because the emissions system is compromised; HELLA lists the SCR warning, emergency operation of this system and higher consumption as effects; and FleetRabbit, which talks about heavy trucks, describes a distance countdown that ends up limiting power. Without a valid signal from the sensor, the car cannot monitor the SCR properly, so it is best diagnosed soon.[2][3][6]
Documented faults related to P2200
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Faults in which this code appears
AdBlue (SCR) system and NOx sensor: the most serious faults by engine and car
- Medium severityFrequency: Very frequent1.5 BlueHDiAdBlue tank and pump failure1.5 BlueHDi engines built up to August 2020 can suffer failures of the AdBlue tank pump module, with a "no engine start" countdown. The whole tank is usually replaced and Stellantis contributes to the cost up to 8 years.Repair: €1,000–€1,500
- Medium severityFrequency: Very frequent1.6 HDiAdBlue tank and pump fault (1.6 BlueHDi)The 1.6 BlueHDi engines (2013-2019) suffer from the AdBlue tank defect of Stellantis diesels: an emissions warning appears with a countdown until starting is prevented. Replacing the tank, with the integrated pump, costs over €1,000 (price in Spain), but there is an extended warranty of up to 8 years.Repair: €1,000–€1,200
- Medium severityFrequency: Very frequent2.0 HDiAdBlue tank crystallisation and failures (BlueHDi)On the 2.0 BlueHDi with SCR and AdBlue (from 2013), the system's tank, pump or sensors can fail or crystallise: a warning light appears, sometimes a false one, and if ignored the car may end up not starting. The OCU has reported it in Spain and Stellantis compensates some of those affected.Repair (garage): €800–€1,200
- Medium severityFrequency: Very frequentOM642Emissions defeat device (AdBlue/EGR) and software update campaignGermany's KBA found indications of emissions manipulation in cars with the OM642 engine (alongside the OM651): AdBlue dosing and the EGR changed between the test bench and the road. Mercedes-Benz denied it, but in 2018 it recalled hundreds of thousands of diesels in Europe.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
Can I drive with code P2200?
The sources treat it as a moderate fault: CarWiki says you can drive, but that it is not recommended without diagnosing it, and HELLA warns that the SCR system may go into emergency operation. The sensible course is to take it to a garage soon, especially if the instrument cluster shows an AdBlue warning or the car loses power.[2][3]
Does the NOx sensor need replacing if P2200 appears?
Not necessarily. The code points to the sensor's circuit, which includes its wiring, its power supply and the communication with the ECU. First the wiring, connectors and power supply are checked and the sensors' live values are examined; if the sensor is faulty, HELLA says to replace it as a complete unit and carry out the adaptation with the diagnostic tool.[2][3][6]
What is the NOx sensor for?
It measures the concentration of nitrogen oxides in the exhaust gases. On diesels with SCR, one before and one after the catalyst make it possible to check that it reduces NOx using the AdBlue, and it is a part fitted to Euro 5 and Euro 6 cars.[3][4][5]
How is P2200 related to AdBlue?
NOx sensors are part of the SCR system, which injects AdBlue into the exhaust to reduce nitrogen oxides. RACE lists them among the common faults of that system, as parts exposed to extreme temperatures that can lose accuracy or fail over time, and HELLA points out that incorrect AdBlue dosing can leave deposits that damage the sensor.[3][5]
Does P2200 mean the same on every make?
Yes as far as the definition goes: codes that start with P2 are generic OBD-II codes. Each manufacturer decides what test sets it and which bank 1 sensor it monitors.[7]
Will I pass the MOT with code P2200?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[8]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- PartsAvatar.ca - OBD II Error Code P2200 SolutionPartsAvatar · Technical documentation · consulted 4 October 2026
- OBD DTC Fehlercode P2200 | Stickstoffoxide (NOx) Sensor - Bank 1CarWiki.de · Other source · consulted 4 October 2026 · in German
- NOx sensor: Setup, troubleshooting and repair instructionsHELLA (HELLA Tech World) · Manufacturer · consulted 4 October 2026
- Nitrogen oxide sensorWikipedia · Other source · consulted 4 October 2026
- Qué es un catalizador SCR: funcionamiento, AdBlue y mantenimientoRACE · Motoring press · consulted 4 October 2026 · in Spanish
- NOx Sensor Failures in Heavy Trucks: The #1 Aftertreatment HeadacheFleetRabbit · Other source · consulted 4 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 4 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish