Categories: Chevrolet

What Are Chevy Diagnostic Trouble Codes?

You may be worried about your Chevy Diagnostic Trouble Codes (DTC) because you see the Check Engine Light (also referred to as the Malfunction Indicator Lamp) of your Chevy car—the engine-shaped light on your dashboard—turning on. When this light turns on, it does signify that something has gone wrong in your car’s system. And when it not only turns on but also flashes, something serious has happened and you should stop your car immediately to prevent further damage. What happens with your car when its Check Engine Light turns on? You can get the answer only if you can read the Diagnostic Trouble Codes that the Check Engine Light represents. There are numerous codes that the light may represent. In order to retrieve the right code, a scan tool is mostly needed.


When your Chevy’s Check Engine Light turns on, you will have to check your Chevy Diagnostic Trouble Codes; however, the codes are actually more often referred to as OBD codes. And to make matters more complicated, you will also encounter another term called OBD-II codes. Should those terms confuse you? Not actually. With a brief explanation below, you can make everything clearer easily.

Your Chevy Diagnostic Trouble Codes are the codes that are used by your Chevy’s On-Board Diagnostic system to notify you about certain problems in your car’s system. Therefore, the On-Board Diagnostic (OBD) system is the computer system that monitors all parts of your car, from the airbags to the engine, and generates fault codes and turns on the Check Engine Light when something wrong occurs, hence the term OBD codes. OBD-II (or OBD2) refers to the standardization of fault code generation that has been used since 1996. In a nutshell, Diagnostic Trouble Codes, OBD codes, and OBD-II codes basically refer to approximately the same thing.

Is a Scan Tool Needed?

In the past, before the OBD-II standardization, a scan tool was not always needed to read Diagnostic Trouble Codes. By seeing the blinking pattern, you or your mechanic could easily determine the problem that occurred in your car. Since the OBD-II standardization, however, a scan tool is needed to get the precise code that signifies the problem to be addressed.

As a Chevy owner, you can either buy the scan tool or let a car service provider do the reading job for you. The price of the scanner is only about $100 with cheaper models also available. Therefore, having one in your disposal is recommended because Check Engine Light that turns on and/or flashes usually need immediate response to prevent more serious damage.

The Code Format

When you plug in your scanner and let it read the code, you will see your Chevy Diagnostic Trouble Codes appearing on the screen. The code consists of five characters. The first is always a letter that signifies the location of the problem: P means powertrain, B for body, C for chassis, and U for user network. The remaining three characters are always numbers. Their interpretation can be generic (shared by all manufacturers) or manufacturer-specific (set by General Motor). Check with General Motor to learn more about all manufacturer-specific Chevy Diagnostic Trouble Codes because not all scanners, which are designed to interpret generic codes, can provide accurate interpretation for those codes.

ibrahim muhammad

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ibrahim muhammad

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