Code P2209The DTC P2209 is a generic powertrain code that is used to detect the “NOx or the nitric oxide and nitrogen dioxide sensor for the Bank 1 side of the engine.” That denotes that it is solely related to the NOx oxides of nitrogen sensors. These are mainly applied in emission systems that are compatible with diesel engines. Their goal is to detect the optimum levels of NOx emission from the exhaust gasses and the combustion engine. The internal computer might have got some foreign objects from the gaseous mixture rather than the average indicators. The input data of the oxygen sensors and the catalytic converter must exert something familiar in the instance.

In simple words, we can aforementioned that the engine control module (ECM) is capable of detecting the nitrogen oxide (NOx) gasses using particular information from the inlet and outlet of the heavy-heated oxygen sensors in combination with the distinctive NOx sensor readings. This DTC is most probably the engine block suggesting cylinder number one.

Working mechanism: NOx Sensor Heater Sense Circuit Bank 1

Most of you do not know the fact that the NOx Sensor Heater Sense Circuit Bank 1 has been established with two Oxides of Nitrogen (NOx) Sensors. These two Nitrogen (NOx) Sensors have different types of working mechanisms. Those two sensors are, 

Let us focus on the upstream NOx Sensor first. It is located on the systematic elbow of the Turbocharger, which is connected with the downpipe. This downpipe is vehemently attached to a corresponding NOx Sensor module.

On the contrary, the downstream NOx Sensor is situated on the pervasive outlet of the Selective Catalytic Reduction (SCR) Catalyst. This has a deep relation with the corresponding NOx Sensor Module. This sensor is attached to the right frame rail. It is surmounted to the warm engine block, making sure that the ambiance is quite in favor of the dissection. P2209 Trouble Code

The NOx Sensor Modules can be changed as you like. Those can communicate with the Powertrain Control Module (PCM) in a diversified way. The NOx Sensor Modules must perform the diagnostics compounding that is correlated with the internal diagnostics. The NOx Sensors play a pivotal role in controlling the efficiency of the SCR Catalyst. That’s how these two types of NOx Sensors work harmoniously to make the car untouchable. 

Causes behind the P2209 Trouble Code:

Let us have a look into the causes behind the emanation of the DTC P2209 in maintaining some proper allocations,

What are the associated parts of the DTC P2209? 

The associated parts are mostly very much crucial in making the most of the abandonment. In this phase, we will see some of the related parts of the NOx Heater Sensor and also find out their role in perceiving the simplest  form of contribution, 

Common Mistakes When Diagnosing the DTC P2209

DTC P2209 is deeply related to the nitrogen dioxide sensor for Bank 1. The very naïve fault the professional does prefers other parts rather than the nitrogen sensor. The checkings of the fuel pressure regulator and DEF pump could be skipped by any means. They may also not check the Fuel injector perfectly as most of the contaminations are done in this section. These are some of the common fallacies that may be eradicated if the professional maintains the hierarchical order in diagnosing the car.

Codes that are similar to the DTC P2209

Some codes are very much similar to the DTC P2209, and the repairing process is also almost the same as these so that these codes can develop a sense of homogeneity in between the codes. Those codes are,

P2205– “NOx Sensor Heater Control Circuit Open Bank 1”

P2206– “NOx Sensor Heater Control Circuit Low Bank 1”

P2208–  “NOx Sensor Heater Sense Circuit Bank 1”

P2212– “NOx Sensor Heater Sense Circuit Intermittent Bank 1”

P2211– “NOx Sensor Heater Sense Circuit High Bank 1”

Complete diagnosis and repairing process of the DTC P2209

The diagnosis and the repairing process of the DTC P2209 are almost the same as the previous codes. Just a little different is that it is solely related to the NOx Heater Sensor. So it would help if you input more focus into this arena. 

Wirings & Sensor

The first stage is to visually check and monitor the electrical wirings and the sensors of the insides. If you find any faulty sensor or connecter, then replace that without any further delay. Then you must attach the OBD2 code with the car and scan for the error codes. After you find the error code try to solve the codes manually.

Exhaust gasket

Then diagnose the exhaust gasket if there is any sort of leakage in this section; if you find leakages, then repair that. Then diagnose the temperature of the exhaust gasses in the catalytic converter. If the temperature is too excessive, then cool it down. 

O2 Sensor

Diagnose the oxygen sensors, which is very crucial, similar to the NOx Heater Sensor. These sensors work harmoniously so that they can serve the air-fuel mixture ratio of the catalytic converter. Repair and replace the oxygen sensors and change the sensor’s hose if it defects.      


Finally, you need to diagnose the PCM or main computer. If it takes a long time to be in operation, then you must update the software package, and by doing that, it can be resistant to all kinds of bugs and error codes. Thus you can diagnose and repair the DTC P2209 simultaneously. In the end, take a short test drive of the vehicle and ensure that the trouble code is wholly eradicated from the system.

Hi, I am Henry, the owner of this website. If you are a DIY car enthusiast like me and are looking for an all-purpose OBD2 scanner, you’ve come to the right place. With 5+ years of experience in the automobile industry, I have in-depth knowledge about most of the OBD2 scanners regarding their software versions, firmware, features, updates, and compatibility. I love reviewing these gadgets after using and testing them personally. As a result, I always try to provide my honest opinion on the overall product quality.

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