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ttiger79, Auto Mechanic
Category: Chevy
Satisfied Customers: 1257
Experience:  ASE Master Certified, Advanced Engine Performance
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1998 gmc: the security light comes on and stays on..truck starts..dies

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I own a 1998 gmc 1500 p/u when you turn the key on the security light comes on and stays on. the truck starts for a second and dies is their a way to reset it.
Yes, there is a way to reset the antitheft system in your truck. It will take a half hour to do this. Here's the procedure:

The following is the Auto Learn Procedure:

1. Momentarily rotate the ignition key to the CRANK position (Do NOT start the vehicle), then release it to the RUN position (Do NOT key OFF in the process).
2. Wait 10 minutes . Observe the SECURITY indicator. Refer to the following list for the appropriate responses:

o If the PASSLOCK(TM) sensor was replaced the SECURITY indicator will flash for the 10 minutes duration.
o If the EVO/PASSLOCK(TM) module was replaced, the SECURITY indicator will flash for a few seconds and then remain ON for the remainder of the 10 minutes duration.
o If the VCM/PCM was replaced with a new programmed VCM/PCM and connected to the vehicle for the first time, the vehicle will start and this procedure may not be necessary.
o If the replacement VCM/PCM was connected to any vehicle at any other time, even momentarily, the SECURITY indicator will flash for a few seconds and then remain ON for the 10 minutes duration.

3. The SECURITY indicator will transition from flashing to ON briefly to OFF after 10 minutes if remaining in the ignition ON position.
4. Turn the ignition switch to the OFF position and wait for 10 seconds .
5. Repeat steps 3-6 two more times. The new security code is ready to be communicated among the PASSLOCK sensor, EVO/PASSLOCK module and VCM/PCM. The new password XXXXX XXXXX on the next ignition lock cylinder cycle from OFF to CRANK to ON (start attempt).

Keep in mind, this will only work if there are no faults in the system. If there is a broken wire or a failed module, this procedure will not work. If it starts and dies, this procedure will most likely work.

Let me know if you have any more questions!
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