When diagnosing an issue with a vehicle, mechanics rely on OBD error codes to tell them where the problem is and what’s wrong. Each time the vehicle’s system detects a problem, it will trigger or “throw” a diagnostic trouble code that a mechanic can assess using a diagnostic tool like the MaxiSYS MS909, MS919, or MSULTRA from Triad Diagnostic Solutions.

But what if a car’s check engine light doesn’t come on? Can a car throw codes without illuminating the check engine light? Let’s find out!

Why a Car Can Throw Codes Without a Check Engine Light

It may be surprising to you, but, yes, a car can throw error codes without signaling the check engine light. But why? As it turns out, the check engine light is not always directly connected to the mechanism responsible for throwing codes. In some instances, there could be a loose connection or even a wiring issue that prevents the check engine light from coming. That being said, there are a couple of other reasons a check engine light may not come on even when codes are thrown. Also, many minor codes or non-critical operational systems do not generate a dash light due to the OEMs not wanting to concern their customers every time a minor issue arises on a non-critical or non-safety system.

A Problem With the Vehicle’s Computer

The first reason that a check engine light may not come on despite codes being thrown involves a problem with the vehicle’s computer. There are two different types of codes that your car’s computer can generate fault codes and information codes. These include:

    • Information codes. Information codes aren’t necessarily indicative of a problem. Instead, they’re meant to provide information about what your car is doing.
    • Engine fault codes. Engine fault codes are thrown when a problem is observed in your car. Typically, this causes the check engine light to come on but not always.

The Check Engine Light May Be Burnt Out

Another reason that the check engine light may not come on despite a car throwing error codes involves a burnt-out check engine light. In this scenario, it is crucial that you have your car’s error codes read by a reliable mechanic who can diagnose and fix the problem.

Does a Check Engine Light Have to Be On to Pull Codes?

Another common question involving the check engine light and error codes is whether the check engine light has to be on in order to pull codes from the system. While most people believe that the check engine light must be on when codes are active, this isn’t always the case. Every modern vehicle comes with a computer system that constantly collects data and tracks every function of the vehicle. Everything from gas mileage, fuel filter life, oil pressure, and electrical are tracked and data stored. So, with the right diagnostic scan tool, automotive technicians can quickly and easily read the codes and data from your vehicle, even if the check engine light isn’t on.

speedometer in car

Can Mechanics Read Error Codes Without the Check Engine Light?

Most mechanics will be perfectly able to read error codes without a check engine light. If the check engine light in your vehicle is on, it’s critical that you have the codes read by a mechanic as soon as possible. On the other hand, if your vehicle begins malfunctioning and the check engine light hasn’t come on, it’s still a good idea to take your car to a mechanic for a diagnostics test. The sooner you identify the issue, the more likely you are to have success in repairing the issue before it gets much worse.

How Are Error Codes Read?

In order to read error codes, a mechanic will plug a diagnostic scanner or code reader into the vehicle’s 16-pin OBD II diagnostic connector. This connector is usually located under the dash and near the steering column of the vehicle. Next, the tool will display the code or codes that are being thrown by the vehicle. In order to read the codes properly, a proper scan tool is required.

Autel’s software is capable of reading codes from thousands of makes and models, which means you’ll get dealer-level service every time!

Reliable Diagnostic Scanning Tools from Triad Diagnostic Solutions

If you run a mechanic shop, you’re going to want to invest in Autel diagnostic tools from Triad Diagnostic Solutions. Whether your shop works on automotive vehicles or heavy-duty commercial vans and trucks, we have just what your technicians need to perform the proper diagnostics and repairs. Our company is the leading provider of Autel diagnostic scanners, and it is our mission to provide the tools you need at a price you can afford.

Offering financing options on all of our products for your convenience – It’s never been easier to acquire the tools you need to keep your vehicles running at their best. We can even help with tech training and support. So, contact us today to learn more! (317) 939-3690.

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