Fault code P2201 is called “Nitrogen Oxides (NOx) Sensor Circuit Range/Performance (Bank 1)” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P2201
Diagnostic code P2201 is a generic code that is defined as a nitrogen oxide sensor circuit performance range mismatch (Bank 1). It is set when the Powertrain Control Module (PCM) detects a failure or malfunction with the NOx sensor itself or the control circuit.
The control module monitors countless sensors to keep your engine efficient, reliable and running. It also actively monitors emissions and makes sure that as few hydrocarbons as possible are released into the atmosphere.
The PCM uses NOx sensors to monitor nitrogen oxide levels in the exhaust to get an idea of the amount of hydrocarbons being emitted. Since NOx is one of the main pollutants that diesel engines produce.
The ECM activates P2201 and related codes when it monitors a mismatch in the operating range of the NOx sensors or their circuits. In most cases, this will be a mechanical failure, especially given the sensor operating conditions.
When the PCM detects an operating range mismatch with the NOx sensor or its control circuit, it sets code P2201, after which the warning light illuminates. If the warning lamp is flashing, it indicates a serious problem which may affect the catalytic converter.
Symptoms of vehicle malfunctions
The main signal that an error P2201 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a fault).
- Increase of harmful emissions.
- Floating revolutions, as well as attempts to stall at idle.
- Skipping engine ignition under load or at idle.
- Reduced engine power output.
- Increased fuel consumption.
- Excessive smoke from the exhaust pipe.
The P2201 error is not considered to be very serious; however, like any problem, it is advisable to address it. With this code, you will most likely not pass the emissions test, as the emissions will be exceeded.
Factors that can cause this error code
The error code P2201 can mean that one or more of the following problems have occurred:
- Defective or damaged NOx sensor.
- NOx sensor is dirty.
- Damaged or worn NOx sensor connector.
- Damaged wiring.
- Sometimes faulty PCM module is the cause.
How to fix or reset OBD-2 code P2201
Some suggested steps for troubleshooting and fix the error code P2201:
- Connect an OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Clear the error codes from the computer memory and test-drive the vehicle to see if the code P2201 appears again.
- If the code appears again, check the cables and corresponding connectors leading to the NOx sensor. Make sure they are not broken or frayed. Repair or replace if necessary.
- Inspect and test the NOx sensor, and replace if necessary if it has failed.
- If faulty PCM is the cause, replace or reprogram it.
Diagnose and repair of problems
Inspect visible damage to the sensor, wiring, and connectors. Then start the diagnostic procedure with the scan tool. To determine if error P2201 is the only error, if not, it may be worth investigating other fault codes first.
If no problems with damaged or corroded connectors are found, perform a thorough inspection of all associated wiring. Repair or replace damaged wiring as necessary.
Check wiring and NOx sensor
If no visible wiring damage is found, prepare to perform reference voltage, ground, resistance, and continuity tests. Be sure to disconnect the sensor from the wiring harness so as not to damage the PCM and avoid a short circuit.
The NOx sensor is part of the control circuit, it must also be tested. Compare all readings on the sensor with those in the manual. Replace the sensor if the reading is out of the specified range or value.
When replacing the NOx sensor, make sure that all connections are secure and that all wiring is secured away from hot components. Then start the engine and allow it to warm up to normal temperature to allow the new sensor to go into closed loop mode.
The main cause of error P2201 is a faulty NOx sensor, so replacing it should solve the problem.
On which vehicles does this problem occur most frequently
Fault code P2201 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Audi (Q7)
- BMW (X5)
- Chevrolet
- Dodge (RAM)
- Ford
- GMC
- Honda
- Mercedes-Benz (Sprinter, Vito, W203)
- Volkswagen (Passat)
- Volvo
Fault code P2201 can sometimes be found with other errors. The most common are the following: P003A, P00AF, P2200, P2202, P2203, P2204, P246F, P2509.
