If You Clear a Code in a Car, Will It Come Back? And What to Do Then?

Diagnostic trouble codes (DTCs) are the result of a computerized diagnostic system that is used to identify problems in your vehicle. Each code is unique, and each code has a specific meaning. If your vehicle exhibits symptoms related to a particular code, it means that the system has identified an issue that needs to be addressed.

Clearing the DTCs highlights

• Difficulty level:Low
• Needed scan tools:Professional tool or app
• Additional equipment:No other tools needed
• Timeneeded:10-15 minutes
• Price in a shop:$150 - $250
• DIY repair:Possible

What are diagnostic trouble codes?

Diagnostic trouble codes (DTCs) are stored in the onboard computer of a vehicle when it detects a malfunction. These codes can be read with a diagnostic scanner and help mechanics diagnose the cause of engine or transmission problems and ultimately repair them.

DTCs identify specific areas of concern within the vehicle's powertrain, such as a malfunctioning spark plug, faulty oxygen sensor, or misfiring cylinder. DTCs are typically expressed in five digits, though some manufacturers use four-digit codes for certain issues.

Each code corresponds to the specific problem that needs to be addressed and can help mechanics quickly diagnose the issue and provide an accurate repair estimate. In some cases, certain DTCs can indicate multiple problems that need to be addressed.

In order to properly repair a vehicle, it is important for mechanics to understand all the codes associated with the particular make and model of the car they are working on. Diagnostic trouble codes should always be read in conjunction with other diagnostic information from auto-scan tools, visual inspections of components and systems, as well as other tests.

By using all the available information, mechanics can get to the root cause of the issue and make sure it is properly repaired.

It's important for vehicle owners to be familiar with DTCs in case their car experiences problems. Knowing what codes are associated with a particular issue can help owners better explain their vehicle's problem to mechanics and ensure more accurate repairs.

Additionally, it's helpful for car owners to know how to read the codes themselves in order to diagnose any issues they may be having. Understanding diagnostic trouble codes is important for anyone who wants to get the very best out of their vehicle.

What are the ways to clear a code in a car?

• Using a scan tool: The most common way to clear diagnostic trouble codes is by using an OBD2 scanner. Most modern scan tools are equipped with the ability to clear diagnostic codes, as well as other functions like resetting monitors and viewing live data.
• Disconnecting the battery: Another way to clear diagnostic codes is by disconnecting the car battery. This will reset all stored trouble codes and also reset the onboard computer. However, this method can have unintended consequences as it may also reset other settings and values stored in the car's memory, such as the clock and radio stations.
• Performing a drive cycle: In some cases, you may be able to clear diagnostic codes simply by driving your car for a certain amount of time. This is known as a 'drive cycle,' and it can help reset the onboard computer's memory, which should clear any stored trouble codes.
• Replacing the faulty component: Of course, if a specific component is causing the trouble code to be triggered, then you will need to replace that component in order to clear the code. Once the faulty part is replaced, you should be able to reset the onboard computer and clear any stored trouble codes.

Regardless of which method you use, it's always best to consult your vehicle's manual for specific instructions on how to properly clear diagnostic trouble codes from your car or truck. If the code remains after attempting any of these methods, it's best to have the vehicle inspected by a certified mechanic in order to properly diagnose the issue.

Will a code come back after you clear it?

Yes, it is possible that a Diagnostic Trouble Code (DTC) can come back after you clear the code. Depending on the specific engine problem, the code may return if the underlying issue is not fixed or addressed.

If a DTC comes back after being cleared, it likely means that there is an underlying issue with your vehicle that needs to be repaired in order for the code to go away permanently. It is crucial to take the necessary steps to diagnose and fix any underlying issues in order to ensure your vehicle is running properly and efficiently.

It may be beneficial to use a scan tool or code reader, as well as other methods, such as visual inspection or mechanical testing, to diagnose the root cause of the problem. Once you have identified and fixed the issue, it is important to clear the code again to ensure that it does not come back. If the code returns after being cleared, you should take your vehicle to a qualified mechanic for further diagnosis and repair.

In short, a DTC can potentially return after being cleared if the underlying issue is not fixed or addressed. It is important to properly diagnose and address any underlying issues in order to ensure that the code does not come back again.

Why may it not be a good idea to clear a code?

Clearing a code can be helpful in certain situations, but it is important to understand that clearing a code does not fix the underlying issue with your vehicle. By clearing the code, you may falsely believe that the problem has been fixed and ignore any warning signs or symptoms of an issue that needs to be addressed. You may erase the diagnostic data that is stored in the vehicle's onboard computer, making it difficult to identify the root cause of a problem.

Furthermore, clearing a code can also lead to unintended consequences. Depending on the specific code, it may reset other settings and values stored in the car's memory, such as the clock and radio stations. Additionally, if you clear a code that is related to an emissions control system, it can lead to legal issues and fines if the root cause of the issue is not properly addressed.

For these reasons, it may not be a good idea to clear a code without properly diagnosing the issue first. Taking the time to understand what is causing a code to be triggered and addressing any underlying issues is the best way to ensure that your car or truck is running safely and efficiently.

What are the most common codes, and what do they mean?

The most common Diagnostic Trouble Codes (DTCs) are typically related to the engine, such as P0300 (random misfires), P0420 (catalyst system efficiency below threshold), and P0171/P0174 (lean fuel mixture). Other common codes include:

• P0455 - Evaporative Emission Control System Leak Detected
• P0128 - Coolant Temperature Below Thermostat Regulating Temperature
• P0340 - Camshaft Position Sensor Circuit Malfunction
• P0440 - Evaporative Emission Control System Malfunction
• P0135 - Oxygen Sensor Heater Circuit Malfunction

Each code is associated with a specific issue or problem in the vehicle that needs to be addressed, so it is important to understand what the code means and how to fix it. Consulting your vehicle's manual or a qualified mechanic can help you properly diagnose and address any underlying issues associated with a particular code.

Bottom Line

Clearing diagnostic trouble codes can be a useful tool for troubleshooting engine problems, but it is important to understand that clearing a code does not fix the underlying issue. It is important to properly diagnose and address any underlying issues in order to ensure that the code does not come back again.

Additionally, you may erase vital diagnostic data in the vehicle's onboard computer that could help you identify the root cause of a problem. Therefore, it is important to consult your vehicle manual before clearing any codes, and also consider taking your vehicle to a qualified mechanic for further diagnosis and repair.