getting code 46 VATS. sometimes it just wont start, if i turn the key to the on postion and wait for the security light to go off and it does, it will fire up. but if the light doesnt go off after 5 seconds and i try to start it, it will crank but wont fire up. i thought the vats system wont even let it crank. i read previous posts about checking the resistance in the key and in the two wires after the lock cylinder, this is what i got:
(all these were checked on my DVM on the 2K setting)
key: .679 ohms
off the wires in off position: .783 ohms
off the wires in on position: goes up to 2.xxx ohms and drops back down to .8xx ohms
anyone know what the problem could be? is that too much of a difference between the key and the wires?

 

There are two items there that could be faulty or have a bad connection here that would cause your problem.
1. the ECM
2. the VATS control module.

BTW, when testing the OHM's resistance in the key use a higher setting on the DVM since the resistance values range from 402 OHM's to 11800 OHM's

 

the ecm is brand new from napa 7730 computer. i bought a 680 ohm resistor because thats what my key read, and put it to the vats, and it fires up no problem. i dont want to bypass the vats for good because i like the security of it. could the problem be with the ignition cylinder? seems like the ohm resistence in the key is good except when it is turned to start it jumps up to 2000 ohms, and that sets the code and the car trys to fire and just dies immediatly after. but is still allowed to crank because the ohms drop down to normal. so i think the problem is in the ignition cylinder, how would i go about checking this? and what exactly is stopping it from running...... spark?

 

What is stopping it from firing is lack of fuel since the VATS system also controls the fuel injectors. When you check the resistance in the key through the lock cylinder is to disconnect that two wire connector under the dash and put the key in the lock cylinder and measure the resistance through those two wire going to the lock cylinder. You do not have to turn the key to the "ON" position to check the resistance value. You might have a wire going bad or a bad contact in the lock cylinder or a worn key.

 

that is news to me, so does that mean if i were to get it to start with the bypass, and then remove the resistor when it is running, will it effect the injectors and make it run different? thanks for all your help

 

I can't say what would happen if you pulled the resistor out while the engine is running since I haven't tried it. It sounds like an interesting experiment that I might try on my car with a spare lock cylinder and key that I have.