P0056 Code: HO2S Heater Control Circuit Bank 2 Sensor 2

If you’re having trouble figuring out what code P0056 means and how to resolve it, read on to learn its definition, possible triggers, and common symptoms.

What Does the P0056 Code Mean?

Diagnostic trouble code (DTC) P0056 stands for “HO2S Heater Control Circuit Bank 2 Sensor 2.” It is logged when the powertrain control module (PCM) detects a possible issue with the heater control circuit of oxygen sensor 2 on Bank 2.

Bank 2 is the side of the engine that does not contain the #1 cylinder. The oxygen sensor 2 located on this bank is also known as the downstream oxygen sensor because it is located after the catalytic converter.

The PCM determines the oxygen content of the exhaustthrough heated oxygen sensors in the exhaust system before and after the catalytic converter(s). The data provided by the oxygen sensors helps the PCM maintain the right air-to-fuel ratio.

When the PCM detects a possible issue with the heater control circuit on oxygen sensor 2 on Bank 2, it logs code P0056. The code may also be set if the PCM perceives that the oxygen sensor is not heating up properly or if the heater wire is malfunctioning. Depending on the severity, other trouble codes may also be logged, such as P0030 and P0036.

If you need help locating the oxygen sensor that may be faulty, read our brief guide about bank 1 vs bank 2. You can also find more information that can help you troubleshoot P0056 on your own in our discussion about why oxygen sensors need heat.

Note: The definition of code P0056 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 P0056 Code?

P0056 is a generic code, so it can have several triggers. Here are the most common:

• Circuit issues
• Broken oxygen sensor
• Failure in the PCM

What are the Common Symptoms of the P0056 Code?

You may notice the following symptoms if you drive a car that has a logged P0056 error code:

• Check engine light is illuminated
• Decreased fuel efficiency

How to Diagnose the P0056 Code

Tip from Richard McCuistian, ASE Certified Master Automobile Technician: You can get an old O2 sensor connector that came from a vehicle like the one you’re working on and connect a tail light bulb to the two wires that are the same color on the connector (white, brown, black, etc.). These two same-color wires are the wires that feed the heater. When you start the truck with this homemade tool plugged into the harness in place of the suspect sensor, the light should come on. If it doesn’t find out why. Don’t neglect to check fuses.

You can get an old O2 sensor connector that came from a vehicle like the one you’re working on and connect a tail light bulb to the two wires that are the same color on the connector (white, brown, black, etc.). These two same-color wires are the wires that feed the heater.

–Richard McCuistian, ASE Certified Master Automobile Technician

To ensure your engine continues performing well, code P0056 should be resolved immediately. However, diagnosing this code can be tricky as it has a number of potential causes.

Keep in mind that the diagnostic and repair steps of this code depend on the specifications of your vehicle. A P0056 code on a Chevymay require a different diagnosis process from a P0056 on a BMW. If you’re not confident in your automotive know-how and repair skills, leaving the diagnosis to an expert is the best course of action. However, if you’d like to see what the diagnostic process might entail, you can check out the video below:

How to Fix the P0056 Code

Like most OBD-II codes, P0056 shares similar triggers and symptoms with other error codes. However, that does not mean that it also shares their solutions. The diagnostic and repair procedures of DTCs vary depending on the vehicle’s year, make, and model. If you are not confident with your automotive know-how and repair skills, it’s best to leave the job to a mechanic.

However, if you’re considering troubleshooting this code on your own, make sure your automotive knowledge is up to date before attempting any fixes. Refer to a repair manual or an online repair database to learn how to resolve code P0056.

Where to Buy a New Oxygen Sensor for Your Vehicle

If your scan tool reads a P0056 code, identify what’s causing the issue. If there are no circuit problems and the PCM is working as it should, you might need to replace the oxygen sensor 2 in bank 2. Luckily, it’s easy to get an oxygen sensor replacement with the help of CarParts.com.

We have a wide selection of premium oxygen sensors sourced from top brands in the industry. They’re all tested during manufacturing, so you can be sure they pass industry standards in terms of quality and functionality.

To start shopping, all you have to do is go to our website and look for our vehicle selector tool. Input your ride’s details to allow our system to narrow down your search to the parts that fit your ride. If you need help, don’t hesitate to contact our toll-free hotline. Our friendly customer service representatives are ready to assist you anytime.

Check out our selection now and order your oxygen sensor today!

Product Mentioned in this Guide

Oxygen Sensor Catalytic Converter