My 1999 Silverado shuts off immediately after start. Security light started blinking on way home from work. Next morning starts then shuts of 2 seconds later. Watched some youtube about bad PASSlock modules. Tore dash apart and my truck doesn't have PASSLOCK module or its located somewhere other than where every Youtube video says it is. Any ideas?




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Wow, that is a big disappointment, I bet... Sounds like you could really be on the right track there with the initial diagnosis (it seems to clearly be a Passlock issue based upon your description). I am fairly new to the Chevrolet platform, so I better not get involved too much on this one. But, there are others on here that know immensely more than I do. I would bet there might be another issue causing this, like a bad wire/ground perhaps, but you better wait for the experts. In the meantime, maybe this can give you some valuable insight.

https://ricksfreeautorepairadvice.com/passlock-fixes/

Hang in there...

Jason

 

Also, I am not sure if you are brave enough to try this, but I found this and have printed off the instructions for my future reference as well.

GM Passlock Security Fix

Again, you may want to wait for wiser folks to get involved, but perhaps this might assist you in case they cannot or you need the vehicle as quickly as possible.

Jason

 

do you have a spare key?