P CODES (POWERTRAIN) P0100 - P0199 P0151

    Definition of Trouble Code P0151 - Oxygen Sensor Circuit Low Voltage (Bank 2 Sensor 1)

    The trouble code P0151 indicates an issue with the oxygen sensor circuit low voltage (Bank 2 Sensor 1). The oxygen sensor is a crucial component of your vehicle's exhaust system, as it measures the oxygen levels in exhaust gases. The sensor sends this information to the Engine Control Module (ECM), which adjusts the air-fuel mixture accordingly. When the oxygen sensor circuit voltage reading is consistently lower than expected, the ECM detects a problem and triggers the P0151 code.

    How to Diagnose Trouble Code P0151

    Follow these steps to diagnose the P0151 trouble code:

    1. Verify the code: First, connect an OBD-II scanner to your vehicle's diagnostic port to confirm the presence of the P0151 code. If other codes are present, diagnose and repair them in the order they appear.

    2. Inspect the oxygen sensor and wiring: Visually examine the Bank 2 Sensor 1 oxygen sensor and its wiring for damage, corrosion, or loose connections. Repair or replace any damaged components as needed.

    3. Check the sensor voltage: Using a multimeter, measure the voltage of the oxygen sensor circuit. The voltage should typically fluctuate between 0.1 and 0.9 volts. If the voltage reading is consistently low, this confirms the presence of the P0151 code.

    4. Test the sensor heater circuit: The oxygen sensor has a built-in heater to help it achieve optimal operating temperature quickly. Use the multimeter to test the resistance and voltage of the heater circuit. Compare the readings to the manufacturer's specifications. If the readings are out of range, replace the oxygen sensor.

    How to Repair Trouble Code P0151

    Follow these steps to repair the P0151 trouble code:

    1. Replace the oxygen sensor: If the oxygen sensor circuit voltage is consistently low or the sensor heater circuit is not within the specified range, replace the Bank 2 Sensor 1 oxygen sensor.

    2. Repair wiring or connectors: If any damaged wiring or connectors were found during the diagnosis, repair or replace them as needed. Make sure all connections are secure and corrosion-free.

    3. Reset the code: After completing the necessary repairs, use the OBD-II scanner to clear the P0151 code. Start the engine and let it run for a few minutes, then check for the presence of the code again. If it does not return, the issue has been resolved.


    Trouble code P0151 indicates a problem with the oxygen sensor circuit low voltage (Bank 2 Sensor 1). By following the steps outlined in this guide, you can accurately diagnose and repair the issue, ensuring your vehicle's exhaust system functions properly and maintains optimal fuel efficiency. Always consult your vehicle's service manual for specific repair procedures and specifications, and if you're unsure about any aspect of the repair process, seek professional assistance.

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