Skip the auto shop - Our mechanics make house calls

P0146 OBD-II Trouble Code: O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 3)

Check Engine Light

P0146 code definition

O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 3)

What the P0146 code means

P0146 is the OBD-II generic code indicating the O2 sensor for bank 1 sensor 3 fails to have a voltage change from between 410-490 mV for more than 74 seconds.

What causes the P0146 code?

  • The O2 sensor for bank 1 sensor 3 does not respond to the fuel cutoff or fuel enrichment by the Engine Control Module (ECM) for more than 74 seconds indicating no response to enrichment.

  • The O2 sensor and mass airflow sensor comparison is misinterpreted by the ECM.

  • The mass airflow sensor is not indicating airflow correctly due to contamination or a defective sensor.

What are the symptoms of the P0146 code?

  • The Check Engine Light will come on indicating a problem.

  • There may be no drive symptoms since the sensor is not used as an input for the engine's fuel/air ratio.

  • If the problem is not isolated to just this code and other codes are retrieved, then drive symptoms would be for that code and not P0146.

How does a mechanic diagnose the P0146 code?

  • Scans codes and document freeze frame data

  • Monitors the O2 sensor data to see if the voltage is moving above or below 410-490 mV

  • Monitors the mass airflow sensor data for responses to throttle changes per specifications

  • Follows the manufacturer's specific pinpoint tests for further diagnosis of the code

Common mistakes when diagnosing the P0146 code

Follow these simple guidelines to prevent mistakes:

  • Do not assume the O2 sensor is bad by replacing a good part; do a complete pinpoint test.

  • Check the mass airflow sensor for proper operation and contaminations from dirt, oil and debris from a compromised air filter or an oil bath type filter.

How serious is the P0146 code?

  • This code can be due to problems with the mass airflow sensor, which is needed to calculate the proper amount of air entering the engine. Along with the O2 sensors, the failure of any of these components will cause the ECM to miscalculate the air going into the engine.

  • The ECM loses control or gets the wrong input from sensors like the mass airflow sensor or the O2 sensor if they are within specification, but incorrect.

  • The O2 sensor by itself will not cause a drive symptom, but will cause a failure during an emissions test.

What repairs can fix the P0146 code?

  • Replacing the O2 sensor if it does not respond

  • Testing the mass airflow sensor for the proper readings per specifications when the engine is off and running

  • Replacing the O2 sensor or mass airflow sensor if contaminated or fails tests

  • Cleaning out the mass airflow sensor to see if readings change

  • Disconnecting the O2 sensor to see if the voltage goes to zero to check the wiring to the sensor

Additional comments for consideration regarding the P0146 code

Check and clean the mass airflow sensor to make sure that it is not causing the O2 sensor input to be incorrect.

Need help with a P0146 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

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...

Related questions

Q: Check engine light on

The code indicates that the purge control system has a problem flowing fuel vapors, even though the system has turned off the control valve. This is most likely caused by a leaking purge control valve. Check the valve to see...

Q: Unresolved leakage problems

Have the oil pressure tested to see if it is low, or the oil sensor is reading wrong. Also have the engine compression tested to see if the cylinder number 2 has a problem or not. The P0302 code...

Q: Misfire caused bad o2 sensor?

As you may know the oxygen sensors which are part of your emissions system read exhaust gases to determine whether or not the appropriate amount of oxygen is present in the exhaust. Based upon this reading, this information is relayed...