2251 real customers worldwide
Technical Description of OBD-II Trouble Code
Intermittent Circuit Issue with Bank 2 NOx Sensor Heater
What does that signify?
This is a standard diagnostic trouble code (DTC) for powertrain issues and is commonly found in OBD-II vehicles. It can be applicable to various vehicle makes such as Mercedes-Benz, Sprinter, VW, Audi, Ford, Dodge, Ram, Jeep, etc.
NOx (Oxides of Nitrogen) sensors are primarily used in diesel engines for emission control. They detect the levels of NOx in the exhaust after combustion in the engine’s chamber. The system then recycles these emissions using different methods. Due to the harsh environment, these sensors are made of a combination of ceramic and a specific type of zirconia.
One of the negative impacts of releasing NOx into the atmosphere is the potential for smog and acid rain. Inadequate monitoring and adjustment of NOx levels can have a significant effect on the environment and the air we breathe. The Engine Control Module (ECM) continuously monitors the NOx sensors to ensure acceptable emission levels in the vehicle’s exhaust.
The ECM calculates the levels of Nitric Oxide and Nitrogen Dioxide gases (NOx) by analyzing data from the upstream and downstream oxygen sensors, along with the NOx sensor readings. This is done to regulate the NOx emissions from the tailpipe for environmental reasons. The “Bank 2” mentioned in the trouble code refers to the engine bank that does not contain the #1 cylinder.
P2225 is the specific code for “Intermittent Circuit Issue with Bank 2 NOx Sensor Heater,” indicating that the ECM has detected inconsistencies in the overall performance of the NOx sensor heater circuit.
It is important to note that diesel engines generate a significant amount of heat, so it is crucial to allow the system to cool before working on any exhaust system components.
Here is an example of a NOx sensor for GM vehicles:
What is the severity of this DTC?
If the trouble codes are ignored and no action is taken to repair them, it could lead to catalytic converter failure. Neglecting the symptoms and causes of these trouble codes may result in further complications for the vehicle, such as consistent stalling and reduced fuel economy. If you notice any of the potential symptoms listed below, it is highly recommended to have your vehicle checked by a professional.
What are some of the symptoms of the code?
Symptoms of a P2225 diagnostic code may include:
What are some of the common causes of the code?
Possible causes for the P2225 NOx sensor code may include:
What are some P2225 diagnostic and troubleshooting steps?
The first step in troubleshooting any malfunction is to research the Technical Service Bulletins (TSB) for known issues with your specific vehicle.
Advanced diagnostic steps are highly vehicle-specific and may require specialized equipment and knowledge for accurate performance. The basic steps provided below should be supplemented with a vehicle year/make/model/powertrain specific repair guide for precise instructions.
Basic Step #1
Always start by clearing the codes and rescanning the vehicle. If none of the Diagnostic Trouble Codes (DTCs) appear as active immediately, take the vehicle for an extended multi-stop test drive to see if they reappear. If only one of the codes is reactivated by the ECM, continue the diagnostic process for that specific code.
Basic Step #2
Next, inspect the exhaust system for any leaks. Black soot around cracks and/or gaskets indicates a leak. Address this issue accordingly, as replacing an exhaust gasket is usually a straightforward task. A fully sealed exhaust system is crucial for the proper functioning of the sensors involved.
Basic Step #3
Using an infrared temperature gun, monitor the temperature of the exhaust before and after the catalytic converter. Compare the results to the manufacturer’s specifications by referring to the specific service manual.
Basic Step #4
If the catalytic converter temperature is within the specified range, focus on the electrical system related to these sensors. Start with the harness and connector of the bank 2 NOx sensor. These harnesses often crack and fail due to their proximity to extreme exhaust temperatures. Repair any damaged wires by soldering the connections and using heat shrink tubing. Also, inspect the oxygen sensors involved in bank 2 to ensure they are not damaged, as this can affect the downstream NOx readings. Repair any connectors that are not making sufficient connections or not locking properly.
It is important to note that this article is for informational purposes only, and the technical data and service bulletins specific to your vehicle should always take precedence.
Professional Service
While we always recommend seeking professional mechanical assistance to resolve this issue, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to be addressed. If you are interested in this option, please upload your ECU file to our portal.
