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Your vehicle’s check engine light usually illuminates once the vehicle’s powertrain control module (PCM) detects a possible issue. If you have a scan tool with you, you can connect it to your vehicle’s OBD port to retrieve the specific error code.

P0146 is an engine trouble code related to a possible issue in the oxygen sensor circuit. Read on to know more about this error code.

p0146 oxygen sensor
If the PCM perceives that the oxygen sensor 3 in bank 1 is not responding as it should, it may set code P0146.

What Does the P0146 Code Mean?

Diagnostic trouble code (DTC) P0146 stands for “O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 3).” It is logged when the PCM perceives that the oxygen sensor 3 in bank 1 is not responding as it should. It may also be logged once the PCM determines that the voltage variation is less than normal during a given period.

“Sensor 3” refers to the sensor located after the catalytic converter (post-cat). Its primary function is to monitor the efficiency of the vehicle’s catalytic converter. The PCM compares post-cat and pre-cat sensor readings to assess the efficiency of the cat-con.

Oxygen sensors dispatch signals to the PCM through voltage variations. A lean condition in the exhaust causes the supplied voltage to drop, while a rich condition in the exhaust causes the voltage to increase.

Once the PCM perceives that the oxygen sensor (bank 1, sensor 3) is not responding as it should or if it detects that the voltage variations are slower than usual for a specific amount of time, it will trigger the P0146 error code.

If you’re planning to fix P0146 yourself, you can get more information in our technical discussion about the downstream oxygen sensor.

Note: The definition of code P0146 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

oxygen sensor p0146
A faulty oxygen sensor (bank, 1 sensor 3 ) can trigger the P0146 code.

What are the Possible Causes of the P0146 Code?

Here are the possible triggers of the P0146 engine code:

What are the Common Symptoms of a P0146 Code?

Here are the common symptoms associated with the P0146 code:

How to Diagnose the P0146 Code

An oxygen sensor circuit malfunction may prove challenging to diagnose. Determining which wire, connector, or harness is causing the issue can be difficult, especially if you have limited knowledge and experience in auto repair.

However, if you’re an experienced DIYer who’d like to diagnose the issue yourself, we recommend consulting a repair manual or an online repair database. These resources will provide you with vehicle-specific troubleshooting and repair information.

engine idling p0146
Engine idling can be a symptom of code P0146.

How to Fix the P0146 Code

P0146 is a generic trouble code, which means it may appear on various makes and models. However, it doesn’t mean that there is one solution that would work for all vehicles.

For instance, repair steps that worked for a P0146 on a Nissan Altima may not work for a P0146 on a Nissan Rogue. This is because vehicle engines may be structured differently per make or model.

If you’re a seasoned DIYer, we recommend consulting vehicle-specific repair manuals. You may also subscribe to an online repair database to help you with your repairs.

Products Mentioned in this Guide

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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