They do not provide live data or tell you which diagnostic monitors have failed or completed successfully. At that point, the code reader will be ready to do its work. If the Check Engine Light comes on and flashes, it indicates a very serious concern. What it will do is provide you with a trouble code, or several codes, that provide a jumping off point in the diagnostic process. P indicates a misfire condition on cylinder 1.
This is much better than it was decades ago, when you'd take the family bus down to the garage for that annual tuneup.
How to Read and Understand Check Engine Light (OBD-II) Codes
After I connected to my car and the code appeared, I didn't know what it meant, and this article gave me information to understand. Browse other content. It will read the same code once until you clear it after checking the said fault. OBD-I diagnostic connectors also come in a variety of shapes and sizes. For instance, if you find a code P, a quick Internet search will reveal that it indicates a fault in one of the oxygen sensor heater circuits. Diagnostic trouble codes DTC are automotive computer codes stored by the on-board computer diagnostic system OBD in your vehicle.