98 5.7 No Start

[Meshanic]

Need help. 98 5.7L Vortec will not stay running. Connected and logged data several times but after I retrieved the stock tune file it will not run. It starts and shuts back down. Allowed 15 seconds to reboot. When I used the LS1a it said boot loader blocked. Tried L31 98 to 00 and was able to retrieve just fine.

Thanks.

[Meshanic]

This truck did have the security light on from the previous owner's attempt at installing a remote start. It always started and ran fine even with the security light on. I wonder if this is the VATS acting up. I'm contemplating purchasing a VIN license, disabling the VATS in the tune and flashing that back into the PCM. Funny though it only started this after I retrieved the tune.
Any help would be greatly appreciated.

[Meshanic]

OK it's alive once again. Disabling the theft deterrant fixed my problem. I've brought Duramax's back to life this way before but I wasn't sure this time. When the others had VATS problems there was an active DTC for the theft deterrant system and several other DTC's that, when looked up in the tune file, showed to be "not reported". This time there was nothing but the symptoms.

If anybody knows why reading the cal data from the PCM set this off I'd be interected to know.

Feel kinda dumb about this thread since it was a simple $99 fix. Hey might as well tune this truck since I'm licensed anyway.

[ChipsByAl]

Most likely since the vehicle started and ran with the Security light on, it was in "fail enable" mode. This is like a limp home mode, so you can get the security system repaired. If the battery is disconnected or in your case the PCM read ( and then reset) the system goes into normal "fail" mode till it is repaired. At this point the truck is "fixed" but without the security in place. If the customer wants the light out he'll need to get the security system put back to stock (ie. wired correctly), diagnosed and repaired. Then you can put the security back in the PCM.
Al

[Meshanic]

OK I get it now. Thanks a lot for that info Al. Disabling the VATS actually turned off the security light too.