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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29395
Experience:  GM Grand Master Technician 2007. 14 years experience.
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1999 GMC: security system..stall..the security light stays on

Resolved Question:

1999 GMC Jimmy 4 wd, battery is in, security system light is on, vehicle will start and run for 10 secs then stall and security light never flashes, and vehicle will restart and stall in this manner all the time. If you turn the key off, the security light stays on. How do you reset the security system? Tried 10 min thing with the key on, doesn't work. Disconnected the battery, light goes off but when you turn the key back on - back to square one. Help please. Jerry.
Submitted: 7 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 7 years ago.
Welcome. If the security light does not flash after you start the engine and it stalls, then security is not the issue. This sounds like there is an issue with fuel supply. I would first start with the fuel filter. Just to be sure about the security reset, HERE are the reset instructions.
GM Tech (Cam) and 2 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
The fuel supply is always at 70 lbs - confident that fuel supply is not problem - in reading Steps for security reset: you lose me at Step 3 because the security light never goes off with any other action but battery disconnect. Once the battery is disconnected and reconnected again, the security light is off. Turn the key to ON, Security telltale comes on. Turn key off, light goes off. Turn key back on, light goes on and stays on until battery disconnect. No cranking involved.
Expert:  GM Tech (Cam) replied 7 years ago.
Ok, 70psi is too high, but that should not cause a start and stall. When it does start, is the check engine light on?
Customer: replied 7 years ago.
70 psi reading is off the fuel rail with a fuel pressure guage...answer to YOUR question is "NO".
Expert:  GM Tech (Cam) replied 7 years ago.
Ok,Have you watched the fuel pressure gauge when the engine stalls?
Customer: replied 7 years ago.
Yes. It always stays in 50 to 70 range.
Expert:  GM Tech (Cam) replied 7 years ago.
Ok, Is there any after market devices like a remote starter installed? Also, did this just start or has it been getting worse?
Customer: replied 7 years ago.
No. Absolutely factory
Expert:  GM Tech (Cam) replied 7 years ago.
Ok, let me see if I am understanding this correctly, you start the engine, it runs for 10 seconds or so, then stalls. Will it do this every time?
Customer: replied 7 years ago.
Yes. Sometimes it will take 3 cranks to start, sometimes just hit the key and it starts. It only runs for a max of 10 seconds. The security light never "flashes" or goes off but stays "steady on". I thought it might be fuel-related too, but I've gone through everything from tank to injectors. I've scanned - no codes - the only thing I can think of is the security system. I received these exact reset instructions from the dealer and it didn't work. I talked to the local GM dealer and he says if the security light doesn't 'flash' ever, then there's something wrong with the security system and there was alternate ways to reboot it but couldn't (wouldn't?) tell me there any way to actually disconnect the security system totally? We bought this vehicle for parts at our shop, and we just want to prove the motor and tranny but can't keep it running long enough due to this issue....
Expert:  GM Tech (Cam) replied 7 years ago.
It is starting to sounds like a module issue. The BCM reads the security data from the sensor and relays that to the PCM. Did you scan the BCM and can you communicate with it?
Customer: replied 7 years ago.
AutoExtra 2000 scan tool. It communicates with the PCM but I don't believe it communicates with the BCM - at least I've never had any codes reported for it. What now? DT running lights come on with key on and when running and when engine stalls, they stay on till key off. Can we get around the BCM? Stupid question but can't hurt to ask....
Expert:  GM Tech (Cam) replied 7 years ago.

No, the engine will not run unless the BCM tells the PCM to do so. Have you tried a capacitor discharge?

Customer: replied 7 years ago.
Don't know what a "capacitor discharge" is.....please explain...
Expert:  GM Tech (Cam) replied 7 years ago.
Remove the battery cables, hold them together for 10 seconds and attach them to the battery again.
Customer: replied 7 years ago.
.....never tried....will try
Customer: replied 7 years ago.



Well, we tried everything. Finally went to the previous owner and paid for all the manuals and remote starters and then went to a dealership. Still haven't gotten it running. This is a dud. Sorry for the waste of your time.