Technical Description of OBD-II Trouble Code
High Circuit for NOx Sensor in Bank 2
What does that signify?
This is a generic diagnostic trouble code (DTC) for the 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 others. 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 technology advances, so do the emission standards set by state and provincial laws. Engineers are constantly developing methods to reduce atmospheric emissions in vehicles to meet and exceed these emission requirements.
The Engine Control Module (ECM) continuously monitors numerous sensors to ensure the engine’s efficiency, reliability, and functionality. It also 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, providing information about the hydrocarbons being emitted. NOx is a primary particulate matter produced by diesel engines. The ECM 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. Soot from the exhaust can accumulate on sensors and switches, potentially affecting their performance. This becomes significant because if the sensor is contaminated, it may not accurately measure the values required by the ECM to adjust the EVAP (Evaporative Emissions) system in accordance with federal, state, or 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 P2216 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 often the cause, especially considering the conditions mentioned earlier.
The P2216 code is set when the ECM detects a high voltage condition in the NOx sensor or circuit of bank #2.
NOTE: The term “bank 2” refers to the side of the exhaust system where the sensor is located. Refer to your service manual for specific details. This manual is the primary resource for identifying the specific sensor among the many possible sensors. 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 on the severity scale, especially when compared to potential hazards in other vehicle systems such as steering, suspension, and brakes. If you have more pressing issues to address, you can prioritize those over this code. 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 P2216 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P2216 fuel trim code may include:
What are some P2216 troubleshooting steps?
Start 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 getting burnt or melted, leading to various problems.
TIP: Allow the engine to cool before working near the exhaust.
Clean the sensor. Remember 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 happens, you may need to apply heat to the threads, but avoid direct heat on the sensor itself to prevent damage. If you are not experienced in using heat to loosen nuts or bolts, it is best to avoid attempting this. If you have any doubts about your skills or abilities, it is always advisable to take your vehicle to a reputable service station.
