Can a Car Throw Codes Without Check Engine Light?

Introduction

The check engine light is a common sight on modern cars. It is designed to alert drivers to a problem with the vehicle’s engine or emissions system. However, there are some cases in which a car can throw codes without the check engine light being illuminated.

How the Check Engine Light Works

The check engine light is part of the vehicle’s onboard diagnostics (OBD) system. The OBD system monitors the vehicle’s engine and emissions systems for problems. When a problem is detected, the OBD system sets a diagnostic trouble code (DTC). The DTC is then stored in the vehicle’s computer.

The check engine light is illuminated when the OBD system detects a DTC that is considered to be serious. Serious DTCs are those that can affect the vehicle’s performance or emissions.

Why a Car Can Throw Codes Without Check Engine Light

There are a few reasons why a car can throw codes without the check engine light being illuminated.

The DTC is not considered to be serious. Some DTCs are considered to be less serious than others. These DTCs may not cause any noticeable symptoms or affect the vehicle’s performance or emissions. As a result, the check engine light may not be illuminated when these DTCs are set.
The OBD system is not working properly. The OBD system can fail for a variety of reasons. If the OBD system is not working properly, it may not be able to detect DTCs or it may not be able to communicate with the check engine light.
The check engine light is burned out. The check engine light is a bulb, and like all bulbs, it can burn out. If the check engine light is burned out, it will not be able to illuminate when a DTC is set.

What to Do If Your Car Throws Codes Without Check Engine Light

If you believe that your car may be throwing codes without the check engine light being illuminated, you should have the vehicle scanned for codes. This can be done at most auto parts stores or repair shops.

If codes are found, you should have them diagnosed and repaired as soon as possible. Even if the codes are not considered to be serious, they may still indicate a problem that needs to be addressed.

Conclusion

While it is possible for a car to throw codes without the check engine light being illuminated, it is not common. If you believe that your car may be throwing codes, you should have it scanned for codes as soon as possible.