My daughter's '97 Lumina is running great after some maintenance and
repairs, but now it is having issues with the anti-theft system. The key (with
its hidden resistor) is not making contact very consistently with the ignition
lock/switch. I want to bypass this key resistance system. I have tested the
resistance of the key's contacts and have attached a photo of my findings.
Anyone ever performed this? Do you know which resistor(s) I'll need to
solder into the security circuit? Thanks in advance for any assistance!

 

There is a list of resistors that equate to 1-15, I don't have it, but you can google it. 7.48K is somewhere in the middle. I'd suggest you go to a locksmith with that, and a new key blank with new ignition switch. The locksmith will cut the key that is the 7.48 k ohm pellet. You can add a 7.50k or whatever resistor across the two orange wires from the ignition switch across the column, but the body control module will not work if that resistor is left installed all the time, hence, replace with a new switch, and key. Also, the two small orange anti theft key switch wires need to be routed across the coulmn as to not be cut, I'd recommend tape them. You can do a re-learn with a different resistor key, again I'd recommend replacing it as leaving the resistor in place all the time will cause issues. Not a hard thing to replace, just be carefull of the clockspring wire for the air bag.

 

VATS Code: Resistance Value In Ohms:
1 402
2 523
3 681
4 887
5 1130
6 1470
7 1870
8 2370
9 3010
10 3740
11 4750
12 6040
13 7500
14 9530
15 11800
This passlock 2 code-resistance, yours will be a "lucky" #13

 

Thanks for the 411 on this, very, very illuminating.

I have heard about inserting a resistor, but I have not read that having the resistor connected at all times will cause issues. Do you know what issues? Seems odd that the ECM would even know the difference that the resistance is consistent and why it would care.

As an aside, who the hell thought this was a good idea? Especially for a sedan like this with basically no need for anti-theft beyond door locks. Corvette? OK. This? Nope.

Anyway, I'm thinking of getting the resistor and installing it, even if I have to put an inline toggle switch as the "anti-theft" device. GM car designers makes me laugh, and curse, so many times I cannot count.

 

If you don't break the circuit on occasion, it will cause issue with the bcm. Toggle switch is fine, but the reason I suggested what I did was to not forget to turn off the VATS

 

I get your thoughts and experience. I am simply a overly logical and annoying person (just ask my wife, haha) and I wanted to know why the BCM would be effected by the literal "key" being in the ignition all the time even when the switch is in the off position. I am terrible about knowing why, but it is something that simply like to know as I make repairs and corrections.
Thanks!!

 

Do you know what wattage the resistor should be rated at? Looks like most resistors I'm finding are rated from .33 watt to 175 watts.

 

1/4 watt would be plenty

 

Regardless of the key in the switch, off, on doesn't matter as the BCM will be reading the resistor all the time. The bcm dosen't power off with the switch, it has to have voltage milli amp to keep it alive.

 

Just to be sure, this error can stop a car while it is idling yes? She just had her Lumina's engine stop at a traffic light and it wouldn't restart (no starter and probably no injectors, I'll check) and she had to have it pushed off the road. Is there a way to check and insure this is the issue? I have checked and had checked the battery, starter, alternator and they're good. Plus the myriad of things we just did to the car a few months ago (literally everything). I trust this PassKey nonsense is it. What an absolutely stupid design to live with for my daughter and me.