Drivers first notice the check‑engine illumination accompanied by a pending code for “O₂ Sensor Positive Current Control Circuit Low Bank 2 Sensor 1.” The power‑supply deficiency can cause the ECM to command a lean fuel mixture, which may manifest as:
Because the fault resides in the sensor‑power circuit, the vehicle will generally remain drivable, but the warning light persists until the underlying issue is cleared.
The positive‑current circuit runs from the ECM to the rear‑side O₂ sensor. Exposure to heat, moisture, or road‑salt can degrade the harness, causing increased resistance and a low‑voltage reading. Even a single compromised pin in the connector can trigger P2241.
Inside the ECM, a dedicated driver transistor regulates the 5 V supply to the O₂ sensor. Over‑temperature events, water intrusion, or internal component fatigue can reduce the output voltage below the sensor’s minimum requirement (typically > 2.5 V), prompting the low‑circuit code.
Occasionally, an outdated ECM calibration misinterprets normal sensor voltage as a fault. This is more common after a major ECU flash or when the vehicle’s software version does not match the hardware revision.
A sensor whose internal heater or signal circuit draws excessive current can pull the supply voltage down. While the sensor itself is a component, the ECM’s current‑control logic will still register a low‑circuit condition, so the primary diagnostic focus remains on the module and its wiring.
– Connect a professional scan tool. Verify P2241 and note the sensor voltage reading (should be ≥ 2.5 V). Capture fuel‑trim values and engine load at the time of the fault.
– Locate the Bank 2, Sensor 1 wire (usually a thick‑gauge 5 V supply). Check for chafing, corrosion, or broken pins. Repair any damaged sections with heat‑shrink tubing and proper crimp connectors.
– With the ignition off, measure resistance from the ECM supply pin to the sensor connector. Values above 1 Ω often indicate a poor connection. Compare against service specifications (typically < 0.5 Ω).
– Back‑probe the supply line while the engine is running. Record voltage at the ECM pin and at the sensor connector. A drop greater than 0.5 V suggests a circuit fault.
– Use the scan tool’s “ECU Information” function to confirm the ECM is responding to live data requests. A communication error may point to a failing module even if wiring is sound.
– If the hardware checks out, download the latest ECM calibration from the manufacturer and flash it using a dealer‑level tool. Verify that the P2241 code does not reappear after a drive cycle.
– Minor board‑level repairs (e.g., replacing a driver transistor) are possible but often temporary. When the ECM shows multiple voltage‑control anomalies or has a history of water intrusion, replacement is the more reliable path.
Typical costs
If continuity and voltage‑drop tests reveal no external wiring defect, yet the low‑current condition persists after re‑programming, the ECM’s internal power‑control circuitry is likely compromised. Repeated board‑level repairs rarely restore long‑term reliability because the driver transistor and associated MOSFETs are subject to thermal cycling and moisture exposure. In such cases, replacing the ECM eliminates the root cause and prevents recurring codes.
Flagship One specializes in VIN‑matched control modules, providing a plug‑and‑drive solution backed by warranty. Modern control modules are complex and integrated with security and immobilizer systems. That’s why choosing a replacement isn’t only about the hardware—it’s about correct programming and compatibility. Flagship One’s units are pre‑programmed to the vehicle’s VIN before shipping, ensuring seamless integration and eliminating dealer‑programming delays.
Service Recommendation: Most issues related to this fault are diagnosed and corrected through inspection, wiring repair, and calibration rather than module replacement. For modules not typically replaced through aftermarket suppliers, diagnosis and repair should be performed by a certified automotive technician with access to factory service information and tooling.
A sensor that fails internally may draw too much current, pulling the supply voltage down enough for the ECM to register a low‑current condition. However, the primary diagnostic focus should be the ECM’s power‑control circuit and wiring, because a faulty sensor is only one of several possible triggers.
Replacement units vary depending on production date and software version, so the correct module is matched by VIN before programming. Expect a hardware price of $600‑$900 plus $200‑$300 labor for removal, installation, and VIN‑specific programming.
The vehicle will generally remain operable, but a lean condition can reduce fuel efficiency and, in extreme cases, cause hesitation under load. It is advisable to diagnose and address the fault promptly to avoid possible long‑term sensor or ECM damage.
A professional OBD‑II scanner capable of live data and voltage measurements, a multimeter for continuity and resistance checks, and, for re‑programming, a manufacturer‑approved flashing tool or dealer‑level software.
A severely loose battery connection can cause overall low‑voltage conditions, but the P2241 code specifically monitors the O₂ sensor’s positive‑current circuit. While a weak battery may exacerbate symptoms, the fault will still originate from the sensor supply line or ECM driver circuit.