P CODES (POWERTRAIN) P0100 - P0199 P0146

    Definition of Trouble Code P0146

    Trouble code P0146 is an error code that occurs when the vehicle's Engine Control Module (ECM) detects no activity in the oxygen sensor circuit for Bank 1 Sensor 3. The oxygen sensor is responsible for monitoring the air-fuel mixture in the exhaust gases, and the ECM uses this data to adjust the air-fuel ratio accordingly. The lack of activity in this sensor can lead to increased emissions, poor fuel efficiency, and engine performance issues.

    How to Diagnose Trouble Code P0146

    Before starting the diagnosis process, make sure to gather the necessary tools and equipment, such as an OBD-II scanner, digital multimeter, and an oxygen sensor socket.

    Step 1: Check for related trouble codes. Use the OBD-II scanner to read any stored codes in the ECM. Note down any additional codes related to the oxygen sensor, as they can help identify the root cause of the problem.

    Step 2: Inspect the oxygen sensor and its wiring. Locate the Bank 1 Sensor 3 oxygen sensor, which is typically found downstream of the catalytic converter. Visually inspect the sensor and its wiring for signs of damage, corrosion, or wear. Repair or replace any damaged components as needed.

    Step 3: Test the oxygen sensor. Use a digital multimeter to check the voltage of the oxygen sensor. With the engine at operating temperature and idling, the sensor should produce a fluctuating voltage between 0.1 and 0.9 volts. If the voltage remains constant or is outside this range, the sensor may be faulty and require replacement.

    Step 4: Test the sensor heater circuit. The oxygen sensor has an internal heater to help it reach operating temperature more quickly. Check the resistance of the heater circuit using a digital multimeter. Refer to the manufacturer's specifications for the correct resistance range. If the resistance is out of range, the sensor's heater is likely faulty, and the entire sensor should be replaced.

    Step 5: Check for exhaust leaks. Inspect the exhaust system for leaks, especially near the oxygen sensor, as they can cause inaccurate readings. Repair any leaks found before proceeding.

    How to Repair Trouble Code P0146

    Step 1: Replace the faulty oxygen sensor. If the diagnostic steps have determined that the oxygen sensor is faulty, replace it using an oxygen sensor socket. Make sure to apply anti-seize compound to the threads of the new sensor before installing it.

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

    Step 3: Clear the trouble code. After completing the repairs, use the OBD-II scanner to clear the P0146 trouble code from the ECM.


    Trouble code P0146 is related to the oxygen sensor circuit in Bank 1 Sensor 3. By following this step-by-step guide, you can diagnose and repair the issue, ensuring your vehicle's emissions, fuel efficiency, and engine performance are all functioning properly. Always remember to clear the trouble code after repairs are completed, and perform a test drive to confirm the issue has been resolved.

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