O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1
P2240 indicates the PCM has detected a malfunction in the positive current control circuit of the Bank 2 Sensor 1 oxygen sensor. This sensor measures exhaust oxygen levels to help the engine control module optimize fuel mixture, and a failure causes inaccurate readings that affect engine performance and emissions.
What You Might Notice
- Check Engine light illumination
- Reduced fuel efficiency
- Diminished engine performance or power loss
- Rough idle or hesitation during acceleration
- Stored misfire codes or lean/rich exhaust fault codes
Most Common Causes
- 1
Defective oxygen sensor
The Bank 2 Sensor 1 oxygen sensor has failed electrically or mechanically, preventing proper positive current control and voltage signal output.
- 2
Wiring or connector issues
Damaged wiring, loose connectors, or corrosion in the oxygen sensor circuit prevents proper electrical communication between the sensor and PCM.
- 3
Exhaust system problems
Exhaust leaks before the sensor location or contaminated exhaust can cause erratic oxygen readings and sensor malfunction.
- 4
PCM or electrical control module fault
In rare cases, the engine control module itself may have a defect in the oxygen sensor circuit preventing proper current control.
How to Diagnose It
- 1
Check Defective oxygen sensor — The Bank 2 Sensor 1 oxygen sensor has failed electrically or mechanically, preventing proper positive current control and voltage signal output.
- 2
Check Wiring or connector issues — Damaged wiring, loose connectors, or corrosion in the oxygen sensor circuit prevents proper electrical communication between the sensor and PCM.
- 3
Check Exhaust system problems — Exhaust leaks before the sensor location or contaminated exhaust can cause erratic oxygen readings and sensor malfunction.
- 4
Check PCM or electrical control module fault — In rare cases, the engine control module itself may have a defect in the oxygen sensor circuit preventing proper current control.
How to Fix It
- 1
Replace Bank 2 Sensor 1 oxygen sensor
Remove the faulty oxygen sensor from the exhaust manifold on Bank 2 (opposite side from cylinder #1) and install a new OEM or quality replacement sensor with proper gasket.
- 2
Inspect and repair wiring and connectors
Check the oxygen sensor harness and connector for corrosion, damage, or loose connections. Repair or replace wiring as needed and ensure all connectors are clean and tight.
- 3
Inspect exhaust system for leaks
Examine the exhaust manifold, gaskets, and piping before the Bank 2 Sensor 1 location for cracks or leaks that could contaminate the sensor or affect readings.
- 4
Clear code and perform PCM diagnostic
After repairs, clear the diagnostic trouble code using a scan tool and road-test the vehicle to confirm the fault does not return. If code persists, have the PCM tested for internal faults.
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