DTC stands for “diagnostic trouble code,” usually a series of five letters and numbers (such as P0300) that tells automotive service technicians – aka mechanics – what’s wrong with your engine, emissions controls and other components according to your vehicle’s on-board diagnostics system.
The acronym also represents some BMW and Mini traction control systems, named Dynamic Traction Control.
Since 1996, technicians have plugged scanners into second-generation on-board diagnostics systems (OBD-II) to read codes that tell them what happened to cause the vehicle’s “check engine” light to come on or problems such as stalling, misfiring or engine knock. When something bad like that happens, OBD-II will store a trouble code to help the mechanic track down possible causes.
You can buy a scanner (probably for less than $100) that will show diagnostic trouble codes in your vehicle, but unless you’re experienced at diagnosing and repairing modern cars, the codes may not be too helpful. As the saying goes, a small amount of information is dangerous in the wrong hands, so most people are better off letting an experienced mechanic dissect the DTCs and do the repairs.
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