On this page, you’ll learn more about the following diagnostic trouble codes:
- P0043 HO2S Heater Control Circuit Low Bank 1 Sensor 3
- P0044 HO2S Heater Control Circuit High Bank 1 Sensor 3
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What Is the P0043 Code?
The definitions of codes P0043 and P0044 are “HO2S Heater Control Circuit Low Bank 1 Sensor 3” and “HO2S Heater Control Circuit High Bank 1 Sensor 3,” respectively. Some code definitions don’t include the bank and sensor number. These codes indicate that your powertrain control module (PCM) or engine control module (ECM) has stated a heater circuit issue within one of your heated oxygen sensors, also called your O2 sensors. As a generic powertrain code, you may find codes P0043 and P0044 in any OBD-II-equipped vehicle.
More About the P0043 Code
Your oxygen sensors measure the amount of oxygen content in your exhaust stream. Most modern vehicles have two types of oxygen sensors, one located in the exhaust manifold and one installed in the exhaust pipe downstream from the manifold. Your PCM utilizes information from both of these sensors to ensure the air/fuel mixture is burning appropriately and giving your vehicle the most efficient level of power. To ensure accurate function, the oxygen sensor needs to warm up to at least around 600 degrees Fahrenheit. This code indicates that there may be a problem with the heater element circuit that allows your vehicle to check engine performance.
What Are the Symptoms of a P0043 Code?
The most common symptom of the P0043 and P0044 codes is just your check engine light turning on. It’s actually very rare to see secondary issues related to this code, especially near the beginning. If you do see any secondary symptoms, you’ll likely just see poor fuel economy and general rough running issues. A faulty oxygen sensor very infrequently causes actual drivability problems, so you’ll probably only see your warning light turn on.
What Are Some Causes of a P0043 Code?
The P0043 and P0044 error codes can have a few different causes. Most frequently, the culprit is a faulty oxygen sensor. However, in some cases, your heater control circuit or voltage feed may be shorted to ground or otherwise connected improperly. Issues with the heater wires and general wiring process can cause the P0043 and P0044 error codes to show up.
How Serious Is the P0043 Code?
Initially, these codes may not seem especially serious. After all, the oxygen sensor heater circuit isn’t exactly the most critical component of your vehicle, so much so that you may not even notice drivability concerns initially. However, issues with your oxygen sensor control circuit can eventually lead to other concerns because your vehicle may not be able to adjust your air/fuel ratio properly. Not only can this lead to issues with fuel consumption, but it can also eventually create additional concerns for your engine over time. That’s why it’s a good idea to treat the P0043 and P0044 codes as fairly serious.
Can I Still Drive with a P0043 Code?
You should be able to drive with the P0043 and P0044 codes active, as this code doesn’t usually result in any severe drivability issues. However, you should still avoid doing so if possible. Problems with your oxygen sensor heater element are likely to develop into related problems with your engine if you don’t fix them and continue to drive your vehicle. If you’re seeing this code, it’s best to stop driving and get help fixing the heated oxygen sensor control circuit.
How Easy Is It to Diagnose a P0043 Code?
The diagnostic process for the P0043 and P0044 codes can be complex because there are many common mistakes you need to avoid. For example, it’s very common for people to just immediately replace whichever oxygen sensor is in the indicated heated oxygen sensor bank. However, the proper repair steps require you to do other steps before replacing this sensor. If you’re not sure how to go through and check for each possible problem, it may be best to trust an experienced mechanic instead of trying to DIY a fix.
How Difficult Is It to Inspect a P0043 Code?
Inspection can also be a difficult part of the process of repairing P0043 and P0044 codes. You’ll need to use a scan tool to determine all the codes you’re dealing with, perform a visual inspection, and possibly use additional tools to check for more information, like a wiring diagram, vehicle-specific repair manual, and digital volt/ohmmeter (DVOM). If this isn’t something you’re especially comfortable with doing yourself, it may be necessary for you to talk to a certified mechanic instead.
Need Additional Help with Your P0043 Code?
One of the biggest components of avoiding issues with your engine is fixing the problem without needing a follow-up repair. If you’re worried about the likelihood of making a mistake and you want a solution the first time, a professional mechanic can help.
To start, you’ll want to find an auto repair shop in your area. While you should be able to drive wherever you’re needed with this code active, getting local repair services can help you avoid feeling like you’re going especially out of the way to fix the problem.
Especially if you’re looking at multiple other codes, the OBD-II database at KBB.com is also a great tool to use, even if you’re planning to take your vehicle to a mechanic. With this database, you’ll be more likely to know what types of repairs you’ll probably need to opt for, even before you talk to an expert.
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