Security System Issue?

macampbell · April 27, 2009

I have a 2000 GMC Sierra 1500 5.3L V8 that I was driving for the past few days without issue. Today I took it for a ride and stopped for gas, after paying I got in turned the key and nothing happened. I have power across the dash, the radio, headlights, hood lights and dome lights all work. I have a yellow security light that flashes upon entry to the vehicle in the message center. When I turn the key I don't her the syllanoid clicking and the truck doesn't even start to turn over. Could this be an electrical issue? A starter? An ignition switch? or A Problem with the security system? Any advice would be greatly appreciated. I don't have the original key and was told yesterday that this was a security issue and that the security system needs to be reset. I replaced the battery becuase it was the wrong model so I know that is not the issue. I guess I need to know if I can rule out the starter, ignition switch and the alternator. I am a novice but would love some help with this one.

bill190 · April 27, 2009

1. Read the owner's manual and see what it says about the security features.

2. Search google.com for the words...

2000 GMC security light

3. Get the proper key from a GM dealer.

Alljackedup408 · April 27, 2009

try getting a new key made at a dealer.. rule that out.. then if it still exsists.. go from there.

macampbell · April 27, 2009

Should I rule out the starter and ignition switch first and then move to the security system. How much does a key like that cost.

Mark

ScottyBoy · April 27, 2009

I personally think yer barking up the wrong tree. Usually, when the security is engaged or acting up the engine will at least crank. I've tested MANY of these trucks doing remote starts. Every time I've tried to remote start one befor hooking up the anti-theft bypass, it would shut the engine down. It would start and run for maybe 2-3 seconds at most and then shut off. A few times it would just crank and not start at all. But I've never seen one not do anything at all due to the anti-theft system (which is called Passlock II). Whenever you install a remote start, the passlock II system has to be bypassed so the truck can start without the key in the ign switch. I would DEFINITELY rule out any starter/battery issues before digging any deeper into the security issue. My bet would be thats what it is. Either a bad starter,bad starter solenoid, bad/corroded battery cable, or even a bad battery.

Just my 2 cents.

bossier62guy · April 27, 2009

Should I rule out the starter and ignition switch first and then move to the security system. How much does a key like that cost.

Mark

What's so special about the key?

macampbell · April 27, 2009

I just called the GMC dealership and they told me there isn't anything special about the key. They said it is not a chip key and that it is only a $10 cut and copy. I think I am looking at a starter or selenoid. Should I test the starter for power with an LED light?

ScottyBoy · April 27, 2009

Should I rule out the starter and ignition switch first and then move to the security system. How much does a key like that cost.

Mark

What's so special about the key?

Theres nothing special about the key itself on an 02. Its just a plain old steel key that key be cut at any locksmith or hardware store. The way the anti theft sytem works is kind hard to explain. It doesn't need a signal from the key like a transponder or chip key. The actual ign switch (key switch) has magnetic sensors in it. These are called "hall effect sensors". What they do is sense the key actually being inside the sitch and physically turning the tumblers correctly. Once the sensors read the key turning the tumblers it will then send a signal with the correct amount of resistance to the ECM. The ECM them sees this signal and allows the engine to start. So basically, if a thief tries to pop out the ign switch and start it with a screwdriver or something, or even force the ign switch to turn (but each tumbler won't turn correctly without the key) the computer won't see the correct resistance code and will not allow the engine to start. This system is called PASSLOCK II, and it came standard on all GM truck starting in 1998. A 97 or older can be stolen with nothing more than a strong flathead screwdriver (if you know what you're doing). I learned about all of this when I worked in a car stereo/alarm shop. You have to use a bypass module to remote start a 98 or newer. The module is triggered by the remote start module. When the remote starter is engaged, it triggers the bypass module to come on, then the bypass module sends the correct resistance code to the ECM (just lik the ign switch would) and the ECM then allows the engine to start. The bypass module duplicates the resistance code(you have to program it to "copy" the code) and then "fools" the ECM into thinking theres a key actually turning the tumblers in the ign switch. Some installers can read the resistance with a DMM when starting the truck and then use resistors to duplicate the correct resistance. But that permanantly bypasses the passlock system. I've always opted to spend a lil more $$ on the bypass module and do it correctly, so the Passlock is only bypassed when the remote start is engaged. Here a LINK that kinda explains how passlock works.

ScottyBoy · April 27, 2009

I just called the GMC dealership and they told me there isn't anything special about the key. They said it is not a chip key and that it is only a $10 cut and copy. I think I am looking at a starter or selenoid. Should I test the starter for power with an LED light?

I would test the starter wire to make sure its getting power when the ign is in the start position. If it is getting power, have the starter tested. You may have to remove it to have it tested. I beleive Autozone, O'reilly and Advance will all test it for free. but I would not buy a starter from Autozone. They are junk. I go there for other things like oil, carwash stuff and to get the free diagnost services and such, but over the years I've learned that none of their parts last more than about a year or so. They do give lifetime warranties on most of their parts, but you have to eat the labor of pulling it, getting it swapped out for a new one and then re-installing it. I'd rather just buy the more expensive parts from O'reilly or NAPA. On one car I used to have, I bought an auto zone alternator and went thru three of them in the 4 years I had that car. The same goes for their duralast brake pads. The only way I'd buy Autozone parts is if I know I'm selling or trading in the vehicle in the next few months or so. And thats exactly what I did when I sold a lil honda civic I had. It needed new brakes and I knew I was gonna sell the car, so I bought the cheap $13 Autozone brake pads for it as opposed to the $38 ones at NAPA.

macampbell · April 29, 2009

The wire connecting the solenoid and the starter was severed. I put a new starter in the truck and it runs and starts fine. Thanks for the help!!

bill190 · April 29, 2009

Well why would a bad starter make the security light come on?

Or is it the case that this light always comes on like this and the security light coming on prior to starting is normal?

ScottyBoy · April 29, 2009

Well why would a bad starter make the security light come on?

Or is it the case that this light always comes on like this and the security light coming on prior to starting is normal?

In my truck, the security light will flash anytime the IGN is off and the drivers door is open. It's a strong posibility that he had the door open when he was trying to start it. I know I usually leave my door open if I'm having engine trouble.