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When you do a code scan for a Check Engine (Malfunction Indicator Light/MIL) and get a P0057, this article will give you an idea of where to start.

What Does the P0057 Code Mean?

Diagnostic trouble code (DTC) P0057 stands for “HO2S Heater Control Circuit Low (Bank 2, Sensor 2).” This code sets when the powertrain control module (PCM) detects an issue with the oxygen (O2) sensor’s heater circuit. In some cases, this code may be also taken to mean that the PCM detects that the voltage coming from the heated oxygen sensor heater circuit is lower than the expected range.

The “Bank 2” in this code’s definition refers to the side of the engine that does not contain cylinder number one. Meanwhile, the “Sensor 2” in this code’s definition refers to the sensor farthest away from the engine assembly.

heated oxygen sensor 2a
The P0057 code sets when the powertrain control module (PCM) detects an issue with the oxygen (O2) sensor’s heater circuit.

Oxygen sensors measure the oxygen content of the exhaust. They’re found either on the exhaust manifold or downstream from the manifold, in the exhaust pipe. The PCM uses the information that oxygen sensors gather for many things, such as controlling and streamlining the correct air-fuel mixture for the combustion process. The PCM uses the information from the second sensor in bank 2 to monitor the efficiency of the catalytic converter.

That being said, if the O2 Sensor between the catalyst and the engine becomes dormant so that the ECM/PCM believes it can’t be trusted, the downstream sensor will be used for fuel trim adjustments.

Many oxygen sensors are equipped with heating elements to help them get up to operating temperatures quicker. When oxygen sensors reach a certain temperature, they produce more accurate readings. The PCM monitors the heater circuits for abnormalities or malfunctions and alerts the vehicle’s user (via malfunction indicator lamp or check engine light illumination) if problems, such as the P0057 code, arise. Other related codes include P0037, P0038, and P0058.

Heated oxygen sensor in the exhaust of a vehicle
Many oxygen sensors are equipped with heating elements to help them get up to operating temperatures quicker.

More helpful information can be found in our article discussing why oxygen sensors need to be heated. If you need more information to locate Bank 2, read our guide about Bank 1 vs Bank 2.

Note: The definition of code P0057 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0057 Code?

There are several possible reasons why the PCM may set the P0057 code. Below are just some of the possible causes for this trouble code:

  • Failed oxygen sensor
  • Wiring issues such as:
    • Shorted or grounded control circuit or voltage feed (depending on the system)
    • Damage to the harness or connectors
  • Failed PCM oxygen sensor heater driver

What are the Common Symptoms of the P0057 Code

In many cases of the P0057 code, you might not be able to experience any noticeable symptoms. However, you may still notice the following signs:

How to Diagnose the P0057 Code

Diagnosing the P0057 code may prove to be quite a challenge. In order to achieve an effective and long-term solution, you’ll have to determine the root cause first. Since there are a handful of possible causes, it will take a bit of time and effort for you to get to the bottom of the problem.

Repair manuals and databases are helpful in cases such as this because they provide important information on OBD-II code repair and diagnosis. These resources contain detailed repair instructions as well as diagrams and illustrations.

If you’re a visual learner, there are other resources you can use to help you diagnose the problem. How-to videos and blogs written by certified professionals are widely available online as well. Below is a video resource that may be helpful especially if you want to know more about the P0057 code:

How to Fix the P0057 Code

Getting an effective solution to codes such as P0057 is a challenge. As stated above, you’ll have to narrow down the potential cause before being able to do anything. In addition, repair instructions differ from vehicle to vehicle. Troubleshooting instructions to address P0057 in Nissan vehicles are different from instructions on how to address P0057 in Toyota vehicles. This is why there can be no single fix-all solution to codes such as these.

Repair manuals and databases are helpful to the seasoned DIYer as they contain detailed and accurate repair information. However, if you’re only starting out and have little experience with repairs such as this, it’s best to leave the job to a certified mechanic or technician instead. This is to avoid errors and mistakes that may cost you a fortune.

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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.

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