Ok I did this mod over the weekend and honestly it was so easy I thought I'd post up my experience.

For the third time my PassKey went south and I was over tearing the steering column apart so I did the PassKey bypass mod.

That little chip in your key is actually a resistor. When you place the key in the ignition switch the resistor completes a circuit to the BCM. The BCM reads the resistance value and if it matches what it has stored it enables the starting and fuel injection system (The actual process is a little more complex but for the sake of saving time that’s close enough). GM used 15 different resistor pellet values, here's a table of the different values.

Pellet Code Key Resistance in Ohms
Nominal Low High
1 402 386 438
2 523 502 564
3 681 654 728
4 887 852 942
5 1130 1085 1195
6 1470 1411 1549
7 1870 1795 1965
8 2370 2275 2485
9 3010 2890 3150
10 3740 3590 3910
11 4750 4560 4960
12 6040 5798 6302
13 7500 7200 7820
14 9530 9149 9931
15 11800 11328 12292

In order to determine the pellet value of your key, take a multimeter set to measure resistance and connect the leads to either side of the pellet in your key. The value should closely match one of the nominal values above. None of the other how-to's I read told me exactly what resistor to buy and I'm no electronics genius so I'll lay it out here. I bought a pack of 1/2 watt, 1.5k resistors from Radio Shack for .99 cents. Since the resistance of my key is the #6 1470 Ohm, I used the 1.5k resistors. The 1.5k resistors actually measured closer to 1470 than 1500.


First you have to remove the knee plate from under the steering column.
Locate the wire leading from the keylock. On my 97 Formula it's an orange wire with two small white wires inside (May be different on your car). Pull that wire gently from the steering column to get enough slack to cut the wire.
Sorry for the crappy pictures, I took them with my cell phone.


On the dash side of this wire is a quick connect. Cut between the quick connect and the steering column and then disconnect the quick connect. This way you aren't soldering under the dash. Strip enough of the two small wires coming out of the quick connect in order to solder the resistor in place. I used a heat shrink insulator to make the whole project look clean and professional. Also available from Radio Shack for about $4 for a pack of assorted sizes.


Make sure to put the insulator over the wires before you solder the resistor in place Solder the resistor to the two small wires, hit the insulator with a blow dryer and then reconnect the quick connector.


Push the whole works back up into the dash and reinstall the knee panel. The whole project cost me about $5.00, and took about 30 minutes, a lot less than the towing bill the first time the sucker went out and a whole lot easier than tearing the steering column apart.

Nice! I might do this as a preventative kind of thing. Will it work on other GM cars? My family has a couple of Buicks with PAsskey.

I don't see why it shouldn't if they're set up the same way cause I know the same thing he done works on the Chevy Camaros.

From what I've read all the PassKeyII systems are pretty similar. The major difference is locating the correct wire running into the column.

And I promise, it's not a matter of "if" it will fail, only "when" will it fail. The wires leading into the keylock flex every time you turn the key, so eventually they will break. There's actually a gouge on the metal outer part of the keylock on my car from the wires rubbing back and forth on it. Unless you get lucky and it happens at home, or you are in the habit of carrying a steering wheel puller with you, you're up the creek without a paddle. I've also read horror stories of the dealer charging upwards of $1000.00 dollars to fix it. The best part is after you do the bypass mod you don't have to spend $50.00 on extra keys any more.

Nice- does the wheel have to come off to do the mod?

No, not as long as you can pinpoint the correct wires. You can do it all from under the column. Took all of about 30 mins. On my 97 it's two small white wires with an bright orange insulator aound them. STAY AWAY FROM THE YELLOW WIRES...lol Those are the airbag, I'd hate to be responsible for you loosing your head.

Wow- thanks man. I like myself purdy

Okay...maybe I can get some help here. I'm having issues on a third gen camaro. The car was a tow-in. The computer was stolen, and another from a same year camaro was installed....No start situation. GM made us a key, but I don't think that it has the right resistor in it, because the security light stays on, and the car doesn't start still. How can I bypass this?

Any help would be appreciated.


Dennis

Ok I don't know if this pertains to a 3rd Gen but on the 4th Gens when you say "computer" there are actually several control modules in the car. The BCM or Body Control Module controls the security system. It "learns" the key at the factory the first time it is inserted into the key lock, if the BCM has been replaced it's a crap shoot trying to figure out the proper key resistance, there are 15 different keys. I'm not sure what would be entailed in reprogramming a BCM.

He's more info complements of Rob (Shoebox)
http://shbox.com/1/pass_key.html

Well, I went for a new tune this summer and had VATS disabled then.