Error Code P2201: What It Means & What To Do?

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When the PCM detects a NOx (nitric oxide and nitrogen dioxide gases) sensor circuit voltage reading that is not within the normal operating threshold for a specific engine bank, the OBD code P2201 is set for engine bank 1. The PCM utilizes exhaust composition and temperature data from the oxygen sensors to calculate typical NOx sensor circuit input data. If this level is not detected, then the code will be stored and the service engine light will be illuminated. Bank 1 refers to the engine bank which contains the number one cylinder.

The PCM uses input data received from the upstream and downstream oxygen sensors to calculate the desired NOx sensor readings for each respective catalytic converter. Upstream oxygen sensor readings tend to fluctuate in conjunction with changing fuel mixture conditions. Downstream oxygen sensors tend to remain steadier then upstream sensors. If the individual sensor readings are too similar in response time or level, a code will be stored and a malfunction indicator lamp will be illuminated.

What causes this problem with the NOx Sensor Circuit Range/Performance Bank 1?

• Faulty catalytic converter
• Bad oxygen sensor
• Faulty coolant temperature sensor
• Faulty MAP/MAF sensor
• Fuel injection component problem
• NOx sensor wiring and harness issues
• NOx sensor circuit problems

1. Engine Control Module - If there is any corrosion or breaks in the internal wiring of the harness, then it can cause a short in the ECM or can also cause corrosion in the ECM through the wiring harness. You can always rely on us as we have best auto parts for our customers.
2. Powertrain Control Module - The onboard computer, or powertrain control module is the brain of the engine control system. Now if the brain is not working properly, then neither is the car engine. Get it replaced before the situation gets worse.
3. Fuel Injector - The fuel injectors are important component of the fuel delivery system that helps in proper utilization of the fuel entering the engine. This not only helps in taking care of the air to fuel ratios in the engine, helping the combustion process but also enhances the performance. Thus, replace faulty injector now!
4. Exhaust Gas Recirculation Valve - It is auto part commonly found on many road going automobiles. It is a part of the vehicle’s exhaust gas recirculation (EGR) system, an emissions system that is designed to recirculate exhaust gases back into the vehicle’s intake so that it can reduce cylinder temperatures and NOx emissions. Purchase top notch exhaust gas recirculation valve from us at economical prices.
5. Electronic Control Unit - Is your car jump starting on reverse polarity? Or are you facing some intermittent starting issues? If yes, then it indicates that your electronic control unit is bad. So it is very important to replace the defective electronic control unit with us at equitable prices.
6. Diagnostic Tools - Buy quality diagnostic tools to check and diagnose OBD code P2201 error with the help of experienced mechanic. Visit us today!
7. Mass Air Flow Sensor - If the sensor is unable to measure the air flow pressure correctly, it will hamper the air intake system and fuel delivery system. Replace faulty sensors immediately.
8. Catalytic Converter - Excessive amounts of unburned gas caused by a misfiring spark plug or a leaky exhaust valve can cause overheating of catalytic converter. Replace your old catalytic converter now!
9. Manifold Absolute Pressure Sensor - Problematic MAP sensor can cause excessive fuel consumption, lack of power, and increased emission from the exhaust. Thus, replace faulty sensors now!
10. Intake Valve - Burnt valve can cause increased fuel consumption, affected engine performance, rough idles and engine stalling and not starting. Thus, replace damaged valves immediately.
11. PCV Valve - Faulty PCV valve can cause increased internal engine pressure, failure of oil seals and gaskets, engine oil leaks and much more. Thus, it is important to replace them, if found faulty.
12. Manifold Gasket Set - Damaged intake gasket can cause engine misfires with affected power, acceleration and fuel economy. Thus, replace them now!
13. Oxygen Sensor - An oxygen sensor plays a vital role in the fuel delivery system and air to fuel ratio mixing functions. Without this sensor proper combustion of fuel cannot take place, thus causing performance issues. Also the exhaust system will not be able to detect the emissions properly if this sensor becomes inactive, resulting in increased emissions from the exhaust. Thus, replace faulty oxygen sensor today!
14. Fluid Pump Control Module - Faulty fluid pump control module will result in the fluid pump not working properly. This will cause transmission issue and erratic behaviors. Replace faulty control module immediately.
15. Engine Coolant Temperature Sensor - The most common symptom which is associated with the issues in the engine coolant temperature sensor is the poor fuel economy. Reduction in the fuel economy would also hinder engine performance. Purchase top notch engine coolant temperature sensor online.

It is essential to know the symptoms of an issue as only then you would be able to solve the problem. So that’s why we have listed out some major symptoms of OBD Code P2201 here:

Common Symptoms

• OBD stored code and an illuminated service engine soon lamp
• No start or engine stall condition
• Drivability issues
• Engine hesitation and lack of engine performance
• Hissing noises when accelerating
• Increased emissions

Want to correct the Trouble Code P2201? Read these points mentioned below:

It is essential to restore the flawed wiring that is in the exhaust temperature/pressure circuit

• Repair or replace the quirky exhaust system parts
• NOx sensor replacement
• Replacement of catalytic converter
• Rehabilitate the defaults in the exhaust temperature/pressure sensor
• Carefully adjust the faults in the powertrain control module
• Recondition the non-functioning injector air sensor

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If you want to easily diagnose this fault code, then all you have to do is to follow the steps which are mentioned below:

• The catalytic converter is used exclusively to reduce exhaust emissions (including NOx) in gasoline and diesel burning vehicles. The catalytic converter is an in line device that resembles a muffler or resonator in exterior appearance although it differs greatly from either internally. The catalytic converter gets much hotter than a muffler when the engine is running and especially immediately after the vehicle has been driven. Retarded ignition timing, lean fuel conditions, and engine misfires can increase catalytic converter temperatures to dangerous levels.
• In some instances, the catalytic converter will reach temperatures that cause it to become “red hot” and present a high risk from fire if flammable liquids are leaked or spilled thereon. The catalytic converter uses a system of interwoven fibers (that contain a high concentrate of platinum) packed tightly into the metal housing to restrict and filter excessive noxious oxide fragments.
• The noxious oxide fragments (created by fuel that has not been sufficiently atomized) are then incinerated by the extreme temperatures (500 to 800-degrees Fahrenheit) found inside of the catalytic converter.
• Begin by inspecting the exhaust system for leaks. If exhaust leaks are detected (particularly before the catalytic converter), repair them as necessary, reset the code, and retest the system. Several tools may be needed to successfully diagnose this code if no exhaust leaks are detected.
• A suitable scanner, a digital volt/ohmmeter, and an infrared temperature gun with a laser pointer will help to perform a thorough diagnosis. Begin with a visual inspection of all wiring and connectors. Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary.
• Always retest the system after repairs are completed to ensure success. If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data.
• Continue by clearing the code and operating the vehicle to see if it returns. This will help to determine whether or not the malfunction is intermittent. After the codes are cleared, test drive the vehicle to see if the code returns. If the code fails to immediately return, you may have an intermittent condition. Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made.
• Start the engine and allow it to reach normal operating temperature. Raise the vehicle on a suitable lift and secure it. Point the temperature gun at the exhaust pipe before and after the catalytic converter in question (this is much easier if the temp gun is equipped with a laser pointer). Compare your findings with manufacturer’s specifications. If your findings do not coincide with what the manufacturer recommends, then the catalytic converter is most likely bad.
• If your findings are in line with the manufacturer’s specifications, then use the scanner and oscilloscope to monitor upstream and downstream oxygen sensor and NOx sensor operation on the affected engine bank.
• The “heater” portion of the NOx sensor is an electrical circuit that is dedicated exclusively to warming up the sensor/s. Most NOx sensors in OBD-II equipped vehicles are of the heated variety. Each heated oxygen sensor has its own integrated heater. By heating the NOx sensor using electrical voltage, the PCM is permitting it to become operational sooner than if it was heated using only exhaust gases.
• This decreases emissions and the time needed for the PCM to enter closed loop mode. Most heated NOx sensors use a battery voltage (approximately 12.6 to 13.8-volts).
• On some models the voltage is delivered via a fused circuit. The heated NOx sensor circuit is completed with a ground supplied by the PCM (with the KOEO or KOER).
• Other manufacturers use a computer controlled supply of battery voltage and a continuous ground (no fuse in needed in this design). You may choose to test voltage to the individual sensor heater circuits (power and ground) using a voltage drop method. Test voltages should be near that of the fully charged battery.
• If the PCM detects a fault in heater system circuit voltage (or resistance) a code will be set and a service engine soon lamp may be illuminated. If no obvious problem is found, then use a scanner to view data from the scanner in question.
• Narrowing the scanner’s data stream to include only this sensor will increase the accuracy and response time of the data stream. Using a digital volt/ohmmeter to obtain live data is also an acceptable method for monitoring sensor function and will provide you with more accurate readings.
• Upstream (pre catalytic converter) heated NOx sensor readings should constantly fluctuate between approximately 100-millivolts and 900-millivolts, after the engine reaches normal operating temperature and the PCM enters closed loop operation.
• Downstream NOx sensors should find a point near the center of a lean and rich condition and remain within 100 to 200 millivolts of that point until a significant engine RPM change is actuated.
• If your live data testing (or the scanner data display) reveals a similar reading, then unplug the NOx sensor connector in question and inspect the pins for signs of damage or corrosion. If the connector is faulty, repair or replace it as required and clear the codes.
• Test drive the vehicle to make sure that the repair was successful. If the connector pins appear to be in good shape, then prepare to perform resistance and continuity testing on the NOx sensor by disconnecting the electrical connector.
• If live data suggests that the NOx sensor is not performing properly, disconnect the connector and test the sensor itself. If the battery voltage feed circuit for the sensor heater indicates “no resistance”, suspect that it is defective. Test the NOx sensor as suggested by the manufacturer and compare your findings with manufacturer’s specifications. Replace the sensor as needed and clear the codes afterward.
• Test drive the vehicle afterwards to ensure that a successful repair was performed. If the NOx sensor conforms to the manufacturer’s specifications, prepare to test system circuits for resistance and continuity by disconnecting the electrical connector/s from all related control modules (especially the PCM).
• Consult the manufacturer’s service manual and perform continuity and resistance testing on all system circuits. Compare your actual findings with manufacturer’s specifications and repair or replace circuits, components, or connectors as required.
• Once the repairs are made, clear the codes and test drive the vehicle to ensure that the repair was successful. If NOx sensor and system circuits are comparable to the manufacturer’s specs, suspect a defective PCM (or another related controller).
• Controller failure is rare and replacement of such will require reprogramming. Remember to diagnose and repair oxygen sensor codes, fuel trim codes, fuel mixture codes, or misfire codes first before attempting to diagnose a NOx sensor circuit code.

Common Mistakes When Diagnosing the P2201 Code

• Intake manifold leakages
• Mass Air Flow (MAF) sensor failure/faulty
• Powertrain Control Module (PCM) failure
• NOx sensor circuit problems
• Wiring and Connection issue