P2240 OBD-II Trouble Code: O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1

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P2240 trouble code definition

O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1

What the P2240 code means

P2240 is an OBD-II generic code for the engine control module (ECM) detecting the air-fuel (A/F) ratio sensor signal is shorted or between the A/F positive and negative terminals of the sensor.

What causes the P2240 code?

The engine control module is detecting a signal is shorted or open between the bank 2 A/F sensor 1 signal wires. This can be an issue with the ECM, A/F ratio sensor, or wiring.

What are the symptoms of the P2240 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.

  • The ECM will ignore the sensor and put the engine in failure mode for fuel control. This strategy may be different between manufactures therefore the drive symptoms may be different. You may have surging, bucking or jerking, misfires, low power, pinging, or other symptoms.

How does a mechanic diagnose the P2240 code?

  • Scans and documents the codes in the ECM and looks at the freeze frame data for failure

  • Checks for any problem with the wiring or connector to the sensor

  • Checks the data to see if the sensor is shorted or open

  • Disconnects the sensor to see if the short goes away, indicating a shorted sensor

  • Checks the connector for corrosion that can cause an open in the sensor circuit

Common mistakes when diagnosing the P2240 code

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to clear the ECM codes after the codes are fixed

  • Failing to check and clean the connector for corrosion before replacing the sensor, the connection may only be okay for a short time before the code returns

How serious is the P2240 code?

Code P2240 is an indication that the ECM is getting a signal from the air-fuel ratio sensor that it may be shorted or open. The ECM cannot control the fuel properly until the signal is fixed. You may have poor fuel mileage and various poor drive symptoms.

What repairs can fix the P2240 code?

Additional comments for consideration regarding the P2240 code

Code P2240 is for one of the A/F sensors and may be accompanied by other engine codes. Some vehicles may have computer software issues pertaining to this code and may need ECM reprogramming. Check for technical bulletins for your application before attempting repairs.

Need help with a P2240 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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