hermit

reading thru these posts i find a lot of questions about the ses light. comes on once in a while, flashes regular, a lot of different situations that people experience with that annoying light. can someone explain or tell me where i can find info. on how the light works. does it ever come on and stay? does it only come on when problems repeat, just flash when something is stored and no longer a problem. perhaps the way it shows up is also telling me something. can anyone help me out here? thanks-great site and valueable info from everyones input!!

GMMerlin

Well I'll try to break it down in the simplest of terms.
When the PCM (computor) sees a fault in the emissions system, it sets a trouble code...depending on the type code (severity of the problem) the PCM will turn on the SES light.
If for any reason the fault is intermittant and it passes the test (a certain amount of times) the PCM will turn off the light, but the code is still stored.
If the problem is severe enough to cause catalyst damage (such as a misfire) the SES light will flash.......A FLASHING SES LIGHT IS A BAD THING!!!!
Any time you have a SES light comeS on, there is a problem...it needs to be looked at and repaired...
CLEARING THE CODES AND /OR RESETTING THE LIGHT BEFORE DIAGNOSING AND REPAIRING THE PROBLEM DOES NOT FIX THE PROBLEM

Proper diagnosis will identify the problem and its cause......diagnosing why a SES light comes on first instead of throwing parts at the problem will save you money and aggrevation in the long run........EGR valves and O2 sensors do not fix every SES light problem

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