How To Check Engine Light Codes Without a Scanner

How To Check Engine Light Codes Without a Scanner

The dreaded check engine light is probably nothing new to car owners (CEL). Anytime there is a problem with your vehicle, this ominous warning could appear on your dashboard. But what precisely is the issue, and how do you resolve it?

Finding and analyzing the stored codes in your vehicle’s on-board diagnostic system is the first step in diagnosing and fixing a CEL issue (OBD). In the past, a specialized scanner tool was needed for this. Today, there are a number of alternatives to spending a fortune on a scanner to check engine light codes.

We’ll go over the fundamentals of CEL codes in this article and show you how to manually check them, use a smartphone adapter, get professional assistance, and use online resources. We’ll also discuss the hazards of operating a malfunctioning vehicle and the significance of promptly resolving CEL issues.

The Basics of CEL Codes

The OBD system of your vehicle stores a diagnostic trouble code when something is wrong (DTC). It is possible to retrieve and decipher this code to aid in problem diagnosis.

Letters and numbers are combined to form CEL codes (e.g., P0171, P0300). These codes are uniform across all makes and models because they are standardized. There are two different kinds of codes, though: generic and manufacturer-specific.

All vehicles, regardless of make or model, are able to read generic codes. They are frequently shortened using the prefix P. (e.g., P0171). These codes may give a broad overview of the issue but may not paint a complete picture.

On the other hand, manufacturer-specific codes are specific to a given make and model. They are frequently shortened using the prefixes B, C, or U. (e.g., B0123). When troubleshooting, these codes frequently offer more thorough information about the issue and are the best place to start.

Manually Checking CEL Codes

Manually checking engine light codes is one of the most affordable methods. A diagnostic trouble code reader, which can be purchased for as little as $20, is all you require.

Consult the owner’s manual or quickly search online to find the diagnostic port location in your car. The port is typically found close to the steering wheel under the dashboard.

After locating the diagnostic port, take the following actions to manually gather and decipher the CEL codes:

  • Do not start the engine after turning the ignition key to the “on” position.
  • Connect the DTC reader to the diagnostic port.
  • To retrieve the codes, adhere to the DTC reader’s instructions. While some readers let you view the codes on a screen, others require you to manually count the CEL’s flashes.
  • Take note of the displayed codes.
  • To determine the meaning of the codes, consult an online resource or a code lookup tool.

Depending on the meaning and severity of the code, decide what to do next. While some problems might be minor and simple to fix, others might need a mechanic’s help.

Alternative Methods for Checking CEL Codes

Alternative Methods for Checking CEL Codes

There are a number of alternatives available if you don’t want to manually check the codes.

Utilizing a smartphone OBD-II adapter and a compatible app is one choice. These adapters attach to the diagnostic port and use Bluetooth to send the codes to your smartphone. After that, you can use the app to get the codes and decipher them.

Seeking Help from a Professional

You can always ask a mechanic or dealership for assistance if you don’t feel confident checking the codes yourself or don’t have access to the required tools. They’ll be equipped with the knowledge and training needed to correctly identify the issue and recommend a solution.

If you need to pay a diagnostic fee, keep in mind that this option might cost more than doing it yourself. In the long run, though, it can save you time and effort, and knowing that the problem is being handled by a pro might give you peace of mind.

Utilizing Online Resources

For code lookup and troubleshooting, there are a ton of online resources available. You can enter the code on websites like and to get a description of the issue and potential fixes. It’s a good idea to cross-reference the information with multiple sources because it’s important to keep in mind that these sources might not always be accurate.

Precautionary Measures

It’s crucial to remember that a CEL can signify a serious issue with your car. Ignoring the problem or delaying repairs can result in more costly issues later on and may even be risky if the malfunction compromises your car’s safety.

After retrieving the CEL codes, it’s always a good idea to seek professional advice if you’re unsure of what to do. They can offer advice on the best course of action and assist you in determining the severity of the problem.


Finally, there are a number of methods available for checking engine light codes without a scanner. These include using a DTC reader to manually check the codes, using a smartphone adapter and app, consulting a professional, and using online resources. To prevent more serious issues and to keep your car safe, it’s crucial to take care of CEL issues right away.

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