accidentally erased check engine code

How to recover erased OBD2 codes if you accidentally deleted them?

You know it has an OBD 2 scanner if you own a car. And when you face a problem in the vehicle, the code of this scanner helps you very much. So repairing your vehicle with the retrieved OBD code can concisely solve the mystery. In 1982, California Air Resources first introduced the OBD to all cars in the state. After that, in 1996, the car manufacturer invented the second generation of this system, called OBD2. This upgraded system came with more capacity and complexity for better control of hydrocarbons, carbon monoxide, oxide of nitrogen, etc. And sometimes, old trouble codes make it easy to repair the car. That’s why it’s very urgent to know.

What is an OBD2 Scanner?

A scanner is attached to it to diagnose some complex electronic problems in a new car. This system mainly scans the car troubleshooting, called the OBD2 scanner. Without this device and training, you need a lot of time and face some issues to solve the car emission problem. And you can’t find the actual case by pulling or interpreting diagnostic trouble codes. This OBD scanner helps you find the problem quickly and save you some money and any big issue happening in further vehicle usage.

The recovering process of erased trouble codes in your OBD2 scanner

Nowadays, every car and vehicle is significantly updated, and the OBD is also used in second-generation ones. This car comes with a complex engine control system, and this also requires expensive equipment to access and analyze the data it stores in a car’s computer. In the meantime, it finds any fault. The unique part of this OBD is that the trouble code you most needed in the OBD has been standardized, so it also has the same meaning across vehicle model manufacturers. If you want, you can buy an inexpensive aftermarket scan tool to help you find the diagnostic codes that are used to troubleshoot simple engine control system problems and maintenance work.Recover OBD2 codes

When you own a car, a scan tool comes with its repair manual, and it can help you find the problem with the system and show how to solve this. And the more you do it by yourself, the more you learn about your car system, how they work, how to maintain it, and other easy ways to repair your car. In the newer vehicle’s second-generation Onboard diagnostic kit, you can use a code reader or scan tool to retrieve the trouble code. You need to connect the device to the data link connector underneath the dashboard on the drive side. Then follow the instructions from the tool or find the solution in the repair manual to retrieve the trouble code. That’s how you can quickly learn about the code and then repair it in a short time.

Trouble code storing place:

When your car faces some trouble in working time, your car computer constantly gets information from sensors and resends the data to the actuator as an electrical signal. The vehicle’s make and model decide how many numbers of the system computer it needs. If you want to know if the car is working correctly, you need the received information with data stored in the computer’s memory to compare. If any time the received signal mismatch a preconfigured value or range value, the computer needs to keep the trouble code and turn on the engine light. Sometimes it waits for another drive cycle to confirm the potential problem. This also varies with the type of failure it detects. But when your car computer proves any possible failure, the memory saves the trouble code and illuminates the engine light to alert you.

They need to retrieve the trouble code to know how serious the problem is. As I told you above, you can get the code through the data link connector with a piece of wire, a voltmeter and turn the ignition key with the help of a reader or scanner. The most famous way to proceed is to follow the instructions in your vehicle repair manual from your manufacturer for your vehicle model and make. If you can retrieve the codes using the code reader or scanner, you can quickly repair them with the help of a manual book.

Deciphering Process of the trouble code:

Some letters and numbers show the trouble code on the car screen. A latter and four number is the structure of this trouble code. Like U0031,P0034,U300 etc. 

  • Letter: The letter starts with the trouble code that shows the overall function system involved with the fault, like P for the powertrain. U for user communication problem, C mean control module problem, etc.
  •  Digit: next, you can notice the standard number 0 or 1. It refers to the particular system of car manufacturer code. The following number tells the function of the system that registered the fault. It shows the problem related to the measurement of fuel and air content going into the car engine. The last two digits mainly point out the component or circuit facing the problem and what type of problem it finds. It also shows you the downstream heated oxygen sensor in the Bank 1 section, which has either detected any problem with the air/fuel mixture or its circuit stopped working. This is the final stage of scanning. After you experience your car, you can quickly find the problem your car face problem.

Storage location about DTC:

The code you find from the code reader is DTC or Diagnostic Trouble Code. You also need to know where you can learn about this code.

  • Car repair manual: your car comes with a car repair manual book provided by the manufacturer. You can at first search the code in there. If you are lucky, you also find the solution there.
  • Scantool manual: the code reader or scan tool also came with a manual book. You can also use this, just like the car repair manual book. 
  • Online car repair forums: if you are still in darkness, you can seek help from the online car repair forums. They are professional and can quickly help you with the problem.
  • The web: at the end, you can google the code. And I think you can find the code here very quickly. 

Restore Process of the precise code:

If you want to restore the deleted code, you need a code reader or scanner first. Your data could be accessed with the reader if your car was manufactured after 1996. The tool needs to be connected to the connector located underneath the dashboard. This is located on the driver’s side. Then you can retrieve the previous code with the help of your car or scanner manual book.Restore Process of the precise code

Sometimes some code may not be fully cleared, and it earned first place. You can only read the ECM or PCM code, but it is a scarce case.

You may wonder how much time you need to restore the previous code. It will appear shortly. A check engine counter or readiness counter must be calibrated between 60-and 70 miles when an engine light is reset.

The retrieving and restoring Process of the trouble code details is given in this article. And when you own a car, after using it someday, I think you can easily catch up with the code and learn how to maintain your vehicle and fix any OBD trouble code.


  • Can I read deleted code?

Sometimes many codes may not be cleared. You can read the deleted code from the car screen for that time.

  • What happens when you delete any code?

The code won’t be erased until you solve it, so your car will make an error if you delete it without fixing it. So if you repair the code successfully, you can delete the code from memory.

  • Will a clear code return?

If you fix the issue and delete the code from memory, it won’t return. But if the problem is still there, the code will come back

1 thought on “How to recover erased OBD2 codes if you accidentally deleted them?”

  1. I have a 2003 mercedes e320, I used an autel obd and accidently erased the codes showing on the scanner, does that mean the codes got erased in my car’s ECU?
    I hope not !

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