P2204 NOx Sensor Circuit Intermittent Bank 1

P2204 NOx Sensor Circuit Intermittent Bank 1

OBD-II DTC Datasheet

NOx Sensor Circuit Bank 1 Intermittent

What does this mean?

This is a generic powertrain diagnostic trouble code (DTC) and is commonly applied to OBD-II vehicles. This may include, but is not limited to, Ford, Mercedes Benz, BMW, VW, Audi, Chevrolet, GMC, Dodge, Ram, Sprinter, etc. powertrain configuration.

Generally speaking, diesel engines produce more particulate matter (PM) and nitrogen oxide (NOx) emissions than gasoline / gasoline engines.

As vehicles evolve, so will the exhaust emission standards of most state / provincial laws. Engineers these days are developing ways to reduce air emissions in most vehicles to meet and / or exceed emission regulations.

The ECM (Engine Control Module) monitors countless sensors at any given time to keep your engine efficient, reliable and running. Not only does it do all of this, but it also actively controls emissions and makes sure to put as few of these hydrocarbons into the atmosphere as possible. The ECM uses a NOx sensor to monitor the level of nitrogen oxide in the exhaust gases to get an idea of ​​hydrocarbon emissions. NOx is one of the main PM produced by diesel engines. The ECM actively monitors this sensor and adjusts the system accordingly.

The exhaust of a diesel engine is one of the dirtiest parts of a car, so keep that in mind. The soot produced in a diesel car's exhaust can, if not better, "bake" sensors and switches in the exhaust, depending on their location. It wouldn't matter much if soot didn't have this distinctive feature. If the sensor is not free of debris, it may not be able to correctly measure the values ​​that the ECM (engine control module) actively requires to set up your EVAP (evaporative emissions) system to comply with certain federal/state/provincial laws. Sometimes when moving from state to state where emission standards differ, aftermarket sensors are sometimes used to meet local emission standards.

The ECM will activate P2204 and related codes (P2200, P2201, P2202 and P2203) when a malfunction is detected in the NOx sensors or their circuits. My experience with this code is limited, but I guess it will be a mechanical problem in most cases. Especially considering the previously mentioned sensor conditions.

P2204 is set when the ECM detects an intermittent failure in the bank # 1 NOx sensor or circuit.

Note. In engines with more than one cylinder bank (e.g. V6, V8), bank 1 is the side of the engine that contains cylinder #1. Hence, the NOx sensor is located in the exhaust of this bank. Refer to your service manual for details for your make/model/transmission. This is the main resource with which you can determine which of the possible set of sensors you are dealing with. They use similar differences with O2 (also known as oxygen) sensors.

Example of a NOx sensor (in this case for GM vehicles):

What is the severity of this DTC?

I would say that in most cases the outlier codes will be quite low on the severity scale. Especially compared to some of the potential hazards in other vehicle systems like steering, suspension, brakes, etc. The point is that if you have a big fish to fry, so to speak, you can put it off for second plan. However, any electrical fault must be rectified immediately.

What are some of the symptoms of the code?

Symptoms of a P2204 trouble code may include:

• Increased emissions of hydrocarbons
• Check engine light is on
• Inappropriate fuel economy
• Unstable idle
• Excessive smoke

What are some of the common causes for the code?

Reasons for this P2204 fuel trim code may include:

• Defective or damaged NOx sensor
• Dirty sensor sensor
• Damaged wiring
• Internal ECM problem
• Connector problem

What are some steps to troubleshoot the P2204?

Inspect the sensor and harness. Sometimes the elements that we subject our cars to are the very cause of your fault. I've seen sensors like this taking pictures of rocks, curbs, snow and ice, so make sure the sensor is intact and looks good. Keep in mind that some of these harnesses may be routed in close proximity to the exhaust pipe, so there is a risk of burning / melting the wires and causing all sorts of problems.

TIP: Allow the engine to cool before working near the exhaust system.

Clean the sensor. Make sure you know that any sensor installed in the exhaust goes through countless heating and cooling cycles. Consequently, they expand and contract so much that they sometimes seize the sensor plug (threaded hole) on the exhaust.

In this case, you may need to heat the threads and NOT directly on the sensor, you risk damaging the NOx sensor in this way. If you have never applied heat to ease the release of nuts or bolts, I would advise you not to start there. That being said, if you have any doubts about your skills / abilities, you should always bring your vehicle to a reputable service station.

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