Hi jason1127. Welcome to the forum. The Engine Computer monitors a number of things and turns the Check Engine light on when it detects a problem with anything that could adversely affect tail pipe emissions. That includes a charging system problem that might result in low voltage to the injectors and ignition coil(s), a sensor problem that results in incorrect information for the computer to act on, an excessively lean or rich exhaust caused by any number of things, and on '96 and newer vehicles, cylinder misfires, typically due to spark plug or injector problems. The power steering pump doesn't fall into any of those categories.
Once the Check Engine light has turned on, even briefly, there will be at least one diagnostic fault code stored in the Engine Computer's memory. That code will lead the mechanic to the circuit or system with the problem, not necessarily the specific part. It is important to not disconnect the battery or let it run dead before reading the codes or that valuable information will be lost.
caradiodoc
Oct 2, 2010 at 12:26 AM
