What happened to Cadillac fault code p0300?

P0300 fault code indicates single cylinder or multi-cylinder fire. Misfire refers to the abnormal combustion of the mixture in the cylinder when the engine is running, which can be divided into partial misfire and complete misfire according to the degree of abnormal combustion. In order to reflect the severity of misfire, "misfire rate" is introduced, which is the percentage of effective pressure caused by partial misfire falling to normal value, or the percentage of misfire cycle in the total cycle in a single misfire.

Misfire detection

1. When the cylinder is on fire, the crankshaft speed will be reduced due to power loss. By monitoring the unevenness of engine speed and combining with camshaft sensor, the misfiring cylinder can be identified.

2. Then calculate the total misfire rate and the misfire rate of each cylinder according to the crankshaft movement, and compare them with the pre-calibrated misfire rate threshold, so as to judge whether to record the misfire fault and misfire type. If the value is greater than the threshold, the engine fault light will illuminate.