security light on, truck wont start

Hi, I have a 2000 Chevy silverado. I recently was having problems with the transmittion not switching correctly. Long story short the shop told me to fix the problem I had to put in
A new transmition as well as a new computer which I did, from another Chevy. It worked for a few days then The truck was not starting and had security light on. Had alarm specialist take look and he said the computer had to be reprogrammed. It was reprogrammed at merles. And was still not working. Its unable to start, starts at random once in a long while. ignition switch was changed and still gave same problem. Took to another shop they had a specialist take a look and he said the computer had to be reprogrammed again. Does anybody have any ideas or ran into something similiar. Also would it be possible to bypass the anti theft system by adding a remote start, or cutting some wires. I just really need to get this truck running, Thanks all help is much appreciated

Hi, I have a 2000 Chevy silverado. I recently was having problems with the transmittion not switching correctly. Long story short the shop told me to fix the problem I had to put in
A new transmition as well as a new computer which I did, from another Chevy. It worked for a few days then The truck was not starting and had security light on. Had alarm specialist take look and he said the computer had to be reprogrammed. It was reprogrammed at merles. And was still not working. Its unable to start, starts at random once in a long while. ignition switch was changed and still gave same problem. Took to another shop they had a specialist take a look and he said the computer had to be reprogrammed again. Does anybody have any ideas or ran into something similiar. Also would it be possible to bypass the anti theft system by adding a remote start, or cutting some wires. I just really need to get this truck running, Thanks all help is much appreciated

If security light staying on you need to get it on a engine/transmission/body capable scanner and get the body code.
Post back code no.
If you have a aftermarket add on security or remote start system remove it and see what it does.

What is engine and model size and transmission and 2/4W?

Engine is 5.3 4wd z72

We also need the code no from body computer security system.

explain the no start .. does the engine crank ?

changing the computer and transmission is not a common repair with shifting issues..what were the shifting issues ? where is the old computer ? what vehicle did the replacement computer come from ?

since I am familiar with your area , you do need a secure properly working anti thieft system for your vehicle ...trucks like ours are the pick for being stolen.

just to be sure about whats going on measure the fuel pressures..53-62 psi is required..if below 50 psi it will not start..also you will get no DTC failure codes.....

Yes after the new tranny was bought it continued to have shifting issues
The guys i took it to told me it was the computer , that mine was not working anymore. So I got one
Off of another Chevy truck I found in a junk yard. The shifting issue went
Away but soon the security light came on and truck was unable to start. The engine cranks
But it won't start. Now these new guys say I need to have computer reprogrammed again.
I'm starting to lose faith tho, and might just take it to the dealer. Before doing so and being charges a fortune aside from what ive already paid

I just wanted to see if anyone else had similar issues or just advice on
How to get it started, we know its the passlock anti theft system just gettin the same
Suggestion from a second shop, on having comp. Reprogrammed. Already did that , bit they said that's what it is. They ruled out. Ignition switch, so what's left

Yes after the new tranny was bought it continued to have shifting issues
The guys i took it to told me it was the computer , that mine was not working anymore. So I got one
Off of another Chevy truck I found in a junk yard. The shifting issue went
Away but soon the security light came on and truck was unable to start. The engine cranks
But it won't start. Now these new guys say I need to have computer reprogrammed again.
I'm starting to lose faith tho, and might just take it to the dealer. Before doing so and being charges a fortune aside from what ive already paid

I just wanted to see if anyone else had similar issues or just advice on
How to get it started, we know its the passlock anti theft system just gettin the same
Suggestion from a second shop, on having comp. Reprogrammed. Already did that , bit they said that's what it is. They ruled out. Ignition switch, so what's left
If a aftermarket alarm or remote start is installed the trucks OEM anti theft has to be bypassed.
The dealer is the only good place to get a VCM reprogramed.
I would suggest you dump the aftermarket remote start and anti theft in the trash can.

Nope no aftermarket alarm has been installed its all stock

Nope no aftermarket alarm has been installed its all stock

Next step is a dealer or a good repair shop.
Or get body computer codes and post back codes.

Yes after the new tranny was bought it continued to have shifting issues
The guys i took it to told me it was the computer , that mine was not working anymore. So I got one
Off of another Chevy truck I found in a junk yard. The shifting issue went
Away but soon the security light came on and truck was unable to start. The engine cranks
But it won't start. Now these new guys say I need to have computer reprogrammed again.
I'm starting to lose faith tho, and might just take it to the dealer. Before doing so and being charges a fortune aside from what ive already paid

I just wanted to see if anyone else had similar issues or just advice on
How to get it started, we know its the passlock anti theft system just gettin the same
Suggestion from a second shop, on having comp. Reprogrammed. Already did that , bit they said that's what it is. They ruled out. Ignition switch, so what's left

If this is the security issue It would start then quickly stall.

still as I stated before check the fuel pressure..this must be 53 -62 psi just key on engine off..... WHAT IS THE PRESSURE POST BACK WHATS UP !

AUTO ZONE SHOULD HAVE THE PRESSURE GUAGE FOR YOU TO USE !

I've been out to your town many times ..

Low battery voltage on starting will sometimes set off the security on the truck. Had a 98 s-10 that sometimes it would start but most times let the engine spin over but not start. Come to find out at starting the voltage droped just enough to let engine spin over but not enough to start. Security kicked in on the low voltage stopping the fuel pump from working. Put new battery on and no problems after that. Security light came on about half the time. Also the computer you got, is it 2 or 4wheel drive chiped. They may be different, don't know thats out of my league but just a suggestion that someone else may know answer to. Good Look

a bad ignition switch can cause similar issues.

I had similar no start issue , a while back and j cat got me squared away with dirty and wet pcm , that is located near battery , had it opened dried cleaned and repacked , not a problem since, however that may not be your problem because here in maine we have 10 months and 2 months of bad sledding, and roads are crappy most of time

anybody tell me what to do ,2000 silverado no start ,security light on with battery light trys to run but dies

anybody tell me what to do ,2000 silverado no start ,security light on with battery light trys to run but dies


disconnect the battery and charge it with a battery charger for a few hours then connect back up to the vehicle. disconnect the negative terminal.

a bad battery can cause these issues.

remove the ignition key from vehicle when not being run.

anybody tell me what to do ,2000 silverado no start ,security light on with battery light trys to run but dies

Best to start a new post on your problem.
Things to check.
Did the secutity and battery light problem happen at sme time?
Does it start and run for 2 seconds?
Try a reset on anti theft system.
With a battery charger or jumper on it.
Key on for 10 minutes untill security light goes out.
Then key off few seconds and then repet key on 10 minutes and off and then on two more times.
Then see if it will start and run.
Let us know how it goes.