OBD Codes - What Are OBD Codes? Video
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Video:What Are OBD Codes?

with Matt Ediger

Your check engine light could indicate a thousand different problems with your car and the only way to figure out what's wrong is to understand OBD codes. Here's a quick guide on what OBD codes are and how to understand them.See Transcript

Transcript:What Are OBD Codes?

Hi, I'm Matt Ediger from Downforce Motoring for About.com, and this is a brief guide to your car's on-board diagnostic system.

OBD Code Definition

Modern cars have what's known as on-board diagnostics or, OBD for short. Since 1996, it's been mandatory that all cars come from the factory fitted with this system. What this system does is allow mechanics to track down almost any problem your car may have. Whether it be a bad o2 sensor or a bad fuel injector, by plugging in a diagnostic scanner, your car can tell the mechanic what's wrong, thereby saving many shop hours tracking down what's making your car run poorly. There are over 10,000 separate codes so making a correct diagnostic is best reserved for licensed technicians.

How to read OBD Codes

You can buy simple to use at-home scanners, but if you can't interpret the thousands of codes, it does little to help you. However, if you're a diehard do-it-yourselfer, there are sites that provide code explanations. Say for instance you get a P1121 code from your Ford car: this means that your throttle position sensor is inconsistent with mass air flow sensor. A majority of these codes are in relation to repairs that should only be worked on by a trained licensed mechanic. Here we have a Saab that has come in for repairs and the scanner has told the mechanic what's going on inside the car's engine. Before the OBD mandate, a mechanic would have to spend hours tracking down possible causes for this problem. So we can see that on-board diagnostics are a great time saving invention when it comes to auto repair.

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