SECURITY LIGHT COMES ON EVERY NOW & THEN

A problem with the instrument cluster gauges is common on your year to 06 . The motors that control the speedometer go bad ! Stepper motors are what they are called . Here is a video on how to fix the problem . How to repair GM Instrument Cluster Speedometer Gauge Stepper

sounds like a bad relay to me..

are your power locks working right .try cycling them lock unlock a couple of times

need to have vehicle scanned the trouble codes will be stored in the computer most auto stores offer thi service for free check ur local area there are a few hundred different codes or problems that can cause ur problems and being interment can also be an electrical connection/harness problem

Sometimes on GM vehicles, the anti theft system can fail. This causes the car to stall and can lock the ignition to prevent theft. If you see a light on the dash that says "security". Then this is your problem. Info and solutions on this site. http://vatspasslockpasskeysecurityhelp.yolasite.com/

This is the relearn process if you replace a key and don`t have a scan tool.You have to get the codes from the Theft Deterrent module to see what could be causing the problem.If your key is worn out it could cause this problem.Try using a different key if you have one.The dealership parts department has a tool to check the keys.Usually done at no charge.Only takes seconds to do.Could also be a bad ignition cylinder.That`s why you need the codes.Other wise you are just spending money and buying parts that you don`t need.Let me know what codes you get and I`ll be glad to help you out.Good luck.

Hi, if you have an aftermarket remote car starter installed, this could be defective, causing this issue. otherwise, there is a lock case that the lock cylinder turns in this cae contains the resistor sensor for the passlock, and could fail, and cause the security system to disable.If this has happened currently, I would scan the system for faults. Good luck...Coop

Yoyu dont mention the mileage on your Yukon but low oil pressure will indeed light the CES light when it reachs o psi. Have you checked your oil? Have you changed your oil and filter. High mileage and poorly maintained motors will eventually wear out and develope low oil pressure. A tempary cure would be to use a higher weight oil 20w50 will get a few more miles out of the old gal if indeed the cam, main or rod bearings have reached their service limit.. Good luck

This means there is a fault in the four wheel drive system, the light reset's each time the key is turned off, then it tests itself after the engine is started, if the fault occurs again the light will come back on.

I have the exact some problem 01 Yukon 5.3 – Sometimes my security light also comes on for no reason? Wonder if this has something to do with the remote starter? When this does happen all I have to do is wait for 15 minutes and it fires up just fine. Pisses me off though…