Your vehicle is one of the necessary items in your daily life. It can make your journey terrible when it becomes damaged. The OBD II codes show you the specific problems of your vehicle. After getting the codes, you can take the car to a repairman. The P0042 is a code that reflects the problematic situation of the heated oxygen sensor of your vehicle. When you find the code on the OBD II scanner, you have to immediately replace or repair the heated oxygen sensor’s control circuit. Otherwise, the vehicle will face a big problem soon. What does the P0042 present to us? What is the solution? In this article, you will get the problems related to the P0042 and its solution. 

Quick View (Reasons)

What is The Meaning of OBD II Code P0042?

The diagnostic trouble code P0042 is a problem related to your vehicle’s oxygen sensor. There are both upstream and downstream oxygen sensors in modern cars. They are located at two different places in a car. There is a catalytic converter in the functional system just under the car. The upstream oxygen sensor is ahead of the converter. It measures the oxygen in the exhaust gas and controls the engine air/fuel mixture. The PCM completes the work of maintaining the variety. The exhausting oxygen must be compared with the surrounding air, and the sensor completes the task efficiently. The translated voltage goes to PCM, and the sensor generates it and makes it appropriate for the necessity of the vehicle. The PCM measures this voltage and controls the injector pulse, which should be compatible with the value. 

On the other hand, the downstream oxygen sensor is on the opposite side of the upstream sensor. It is located behind the catalytic converter of the car. The downstream sensor has significant work for the vehicle. The downstream sensor checks its efficiency when it leaves the converter and prepares the sensor free from hampering. When it goes to the car’s converter, it contains the oxygen content of the vehicle. How does an O2 sensor work

Modern vehicles have standard features to maintain speed, efficiency, and extraordinary performance. They use heated oxygen sensors (HO2S) to operate the engine’s temperature faster. A heating element of the sensor helps to fulfill the work. Thus it allows PCM to utilize signal input. It enables them to have appropriate fuel control and lower discharging. So, the signal input is necessary for maintaining the sound condition of the vehicle’s oxygen sensor.  

Symptoms of The Trouble Code P0042

You must know the symptom if you want to ensure that your vehicle is problematic and that the OBD II scanner may show the P0042 trouble code. Only one sign is present before you get the P0042 code on the OBD II scanner. The symptom is turning on the engine light. The engine light shows that your vehicle’s heated oxygen sensor is problematic and needs to check through an OBD II scanner. So, when the engine light becomes on, check the error code through the scanner and get ready for the solution. 

Common Causes:

Some problems cause the turning on of the engine light. The light indicates that your vehicle is problematic. You have to check the error code through an OBD II scanner when you get it. After scanning, you have reached the P0042 code. Do you know which parts of the car are problematic? Let’s see the result. check engine light

There are two sides, including the power and ground sides of the 02 sensor heater circuit. If any side is problematic,  the OBD II scanner will show you P0042. The result indicates that you have to repair the sensor heater circuit fast. 

If the circuit of the sensor heater element is open, the OBD II scanner will present the P0042 trouble code. It shows you that The rotation of the O2 sensor heater is open. It may cause a problem with your vehicle’s sensor. So, when you get the code, immediately go to the repairer and buy a new circuit if the old one is hampered. 

When the O2 sensor heater element’s resistance is high, the OBD II scanner will show you the P0042 code. It means you have to repair the sensor as the heat remains normal. So, you have to take your car to the mechanic’s shop. 

Is The P0042 Code Serious?

Some people can get the service engine light on and check the OBD II code. Then they can find the P0042 code and search for the solution quickly. But what should you do if you are at a distance from the city and can not get a repair fast? You have to know if the problem is severe or not.obd2 check engine codes

The P0042 is not a severe issue for your vehicle. The malfunction of the heater control circuit can spoil your vehicle’s fuel economy. But, it does not cause any unwanted happenings like an accident during a long journey. So, you can repair the car after coming back to the city. 

Common Mistakes in Testing The P0042 Error Code

The P0042 is such a code that causes a standard error when you check it and want to repair it. There are some necessary tests to diagnose an ethical problem with a vehicle. But, the P0042 does not perform all the tests required to identify the issue correctly. So, when you get the code, you have to verify the problem of the sensor by testing it individually. 


The error code P0042 is not severe and does not hamper your relaxation in traveling. But, it is harmful as it causes the expense of your vehicle’s fuel. So, you have to repair it if you want to save money by preventing the unnecessary cost of energy. You will soon fix the heated oxygen sensor problem and get better driving when you can get a good repairer. 

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Kevin Nicholas is an automotive technician who is a genius at software and hardware-related issues. He manually tested more than a hundred OBD scanners and gave his honest opinion on whether the device was worth the money or not. His in-depth OBD review articles help people choose the right product, whether it is a European, American, or Asian vehicle. He completed his Automotive Specialized Training Course at Universal Technical Institute and has more than 15 years of experience in the field.

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