The powertrain control module (PCM) uses the oxygen (O2) sensor to detect the concentration in the exhaust gas. Together with the engine coolant temperature (ECT) and throttle position (TP) sensors, the O2 sensor helps the PCM determine the right amount of air-fuel mixture for optimum engine operation. If the PCM is unable to detect a signal from the O2 sensor, a P2240 trouble code will be logged by on-board diagnostics (OBD).
Diagnostic trouble code (DTC) P2240 stands for “O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1.”
The O2 sensor is a thimble-like device located in the exhaust stream near the catalytic converter (usually on the exhaust manifold or exhaust pipe).
The sensor sends a signal to the PCM, which is calculated by measuring the differences between the oxygen content of the surrounding air and the oxygen content of the exhaust. Feedback is then sent to the engine computer, which lets it keep the air-fuel mixture close to the stoichiometric mixture as much as possible.
An open-loop operation in the engine occurs when the PCM is calculating the air-fuel mixture without the help of the O2 sensor. This can lead to an overly rich or lean mixture and affect engine performance.
Note: The definition of code P2240 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.
DTC P2240 can be logged in vehicles with an OBD-II system. However, keep in mind that the steps for diagnosing this code can vary depending on vehicle specifications. Diagnosing this code might require you to use a scan tool and multimeter, which can be confusing if you’re not well-versed in automotive repair. Under these circumstances, it’s best to leave the job to the pros.
It can be confusing to resolve a P2240 code on your own if you lack the necessary DIY skills and technical knowledge to do so. If you think you can’t handle the task on your own, it’s best to seek the help of a trained professional to get the job done. This will also ensure that all steps and protocols are followed correctly.
But if you’ve had your fair share of resolving trouble codes on your own, then you already know that there’s not one manual that will work for every make and model. Before you begin, make sure you’re equipped with the right tools and vehicle-specific repair information like those from Chilton or an ALLDATA subscription.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.