panman71

trying to start a c5 with programed key, what would keep it from cranking engine, after about 3 attempts it starts cars computer is issuing service requests. any security issues that would stop cranking.

Ill try to clarify turning the key no action, security light is illumated. key wont crank engine till after about 3 attempts of turning key it will crank and start . any one know of a no start condition in the program?

Sunwarrior

Vats key system, old and not used anymore. It can leave you stranded. Your car will do everything but crank up. How many keys do you have? Does it do it on both keys? If on both keys the piece that makes contact with the keys could be worn ( not making good contact) check key with ohm meter to determine which key you and order another one. I ordered 2 new keys from national auto lock service @ www.michaelhyde.com. Ace hardware cuts them for free here, if you have your own key blank.
Google vats keys tons of info
Basically the Vats system is what tells the computer it's okay to start your car. GM created the system to prevent theft of many different cars back in the day. There are you tube video's of how by pass the vats system resistors on line.
https://www.clksupplies.com/products/gator-vats-bypass-module

panman71

thanks, will look into it. im trying to help a friend on this one.

panman71

The problem went away after she started using the car regular, battery died, new battery, then i wont turn over i jumped the clutch switch cleaned both keys an sprayed the ign. switch and brushed its inside with a stiff nylon brush. no dice! supposedly a new starter a year ago.. other than the vat switch any other condition that would cause a no crank condition. crank as in turn over.

RedRiderZR1

Really should put this in the c5 tech section. Quite a few electrical people in that section to help you out. Don't think they come here in the scan and tune section. Lots more traffic over there.