Technical Description of OBD-II Trouble Code
Low Circuit in Bank 2 NOx Sensor
What does that signify?
This is a generic diagnostic trouble code (DTC) for powertrain and is commonly found in OBD-II vehicles. This can apply to various vehicle brands such as Ford, Mercedes Benz, BMW, VW, Audi, Chevrolet, GMC, Dodge, Ram, Sprinter, and more. While it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
In general, diesel-fueled engines produce higher levels of particulate matter (PM) and Nitrogen Oxide (NOx) emissions compared to gasoline engines.
As vehicle emission standards have evolved, engineers have been developing methods to reduce atmospheric emissions in order to comply with and exceed emission requirements set by state/provincial laws.
The Engine Control Module (ECM) constantly monitors numerous sensors to ensure the efficiency, reliability, and functionality of the engine. Additionally, it actively monitors emissions to minimize the release of hydrocarbons into the atmosphere. The NOx sensor is used by the ECM to measure nitrogen oxide levels in the exhaust and determine the amount of hydrocarbons being emitted. NOx is a primary particulate matter produced by diesel engines. The ECM continuously monitors this sensor and adjusts the system accordingly.
It is important to note that the exhaust of a diesel engine is a particularly dirty area of the vehicle. Soot from the exhaust can accumulate on sensors and switches, potentially affecting their performance. This becomes significant due to the unique characteristics of the soot. If the sensor is obstructed by debris, it may not accurately measure the values required by the ECM to adjust the Evaporative Emissions (EVAP) system in accordance with federal/state/provincial laws. In some cases, aftermarket sensors are used to comply with local emission standards when traveling between states with different regulations.
The ECM triggers the P2215 code and related codes (P2214, P2215, P2216, and P2217) when it detects a fault in the NOx sensors or their circuits. While my experience with this code is limited, it is likely that mechanical issues are the most common cause, especially considering the conditions mentioned earlier.
The P2215 code is set when the ECM detects a low voltage condition in the bank #2 NOx sensor or circuit.
NOTE: The term “bank 2” refers to the side on which the sensor is located in the exhaust system. Refer to your service manual for specific details. This is the primary resource for identifying the specific sensor among many possibilities. Similar distinctions are made for O2 (oxygen) sensors.
Here is an example of a NOx sensor for GM vehicles:
What is the severity of this DTC?
In most cases, emission-related codes are relatively low in severity compared to potential hazards in other vehicle systems such as steering, suspension, and brakes. Therefore, if you have more pressing issues to address, you can prioritize those first. However, it is important to address any electrical faults with a sense of urgency.
What are some of the symptoms of the code?
Symptoms of a P2215 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P2215 fuel trim code may include:
What are some P2215 troubleshooting steps?
Begin by visually inspecting the sensor and its harness. Sometimes, external elements can cause faults. I have seen sensors like these damaged by rocks, curbs, snow, and ice, so ensure that the sensor is intact and in good condition. Keep in mind that some harnesses may be located close to the exhaust, increasing the risk of wires becoming burnt or melted, leading to various problems.
TIP: Allow the engine to cool before working near the exhaust.
Clean the sensor. It is important to note that sensors mounted in the exhaust undergo numerous heating and cooling cycles. As a result, they may become stuck in the sensor “bung” (thread hole) due to expansion and contraction. If this occurs, you may need to apply heat to the threads, but avoid direct contact with the sensor to prevent damage. If you are unfamiliar with using heat to loosen nuts or bolts, it is advisable to seek assistance from a reputable service station.
