PadreSmith

iTrader: (24)

I have a bcm from the junk yard. I would like to use this bcm because of the keyless entry function it has. But i don't know what resistance value it is looking for to make the vats system happy. I only have the bcm and not the key/resistor chip.

So my question is can I scan or measure values on the bcm to find the matched resistance value?

wrencher

iTrader: (2)

That would be a pass-key II system then. it does not use resistor pellets/readers to enable the security system.
It uses a hall effect switch in the lock cylinder & the BCM communicates the OK to start/fuel to the PCM via the LAN.
Not as easy to bypass those systems asthe old ones.

carfreak07

iTrader: (10)

I dontknow of a way that you can read the resistance from the bcm.....if you could get back to the yard and measure the resistance on the key with a voltmeter then you could get a NEW corect number key.....1-15 and have it cut the same as the one in your ignition and you would be ready to rock. Without that resistance, your in a pinch.....I know You understand what is going on so I wish you the best......I recently had a similar issue, it took alot of patience but i finally got the whole thing down pat and really understand the system now. if you need to know the resistance values of the numbers 1-15, pm me and ill send them to ya. good luck!!

PadreSmith

iTrader: (24)

Yea my terminology may be off on the vats/pass-keyII. I have a 2002 firebird bcm and the car I got it from is long gone. I would have taken the key with resistor pellet if it was available. Thanks for the help so far.

2002_Z28_Six_Speed

iTrader: (19)

Maybe you could explain this to the yard and get a photocopy of the salvage title. Take that to the dealer and say you want a key made for a race car.

PadreSmith

iTrader: (24)

No it was last year that I got the wiring harness. I just got a renewed interested in this project and dug it out of the garage. So its been quite awhile since the car was crushed. I am making a race car though

fast377

iTrader: (52)

Just go to radio shack and buy enough resistors to come up with these values:
• 402 ohms (acceptable range 386-438)
• 523 ohms (acceptable range 502-564)
• 681 ohms (acceptable range 650-728)
• 887 ohms (acceptable range 850-942)
• 1130 ohms (acceptable range 1085-1195)
• 1470 ohms (acceptable range 1411-1549)
• 1870 ohms (acceptable range 1795-1965)
• 2370 ohms (acceptable range 2275-2485)
• 3010 ohms (acceptable range 2890-3150)
• 3740 ohms (acceptable range 3590-3910)
• 4750 ohms (acceptable range 4560-4960)
• 6040 ohms (acceptable range 5798-6302)
• 7500 ohms (acceptable range 7200-7820)
• 9530 ohms (acceptable range 9149-9931)
• 11800 ohms (acceptable range 11328-12292)

Then just wire each one into the plug at the bottom of the column until you find one that works. Give that value to the dealer and have them cut you a key.

PadreSmith

iTrader: (24)

^^^^^ That is probably eventually going to happen. I have at least two resistors to try already. Buying 13 more won't hurt too bad. But it still leaves me wondering if there is a way to scan the bcm with some type of electrical tool. Electronics are not my department so I don't know if such a scan tool exists.

I was hoping someone would say something easy like just measure between
pin#_ and pin#_ and record the value. If only it was that easy right?

carfreak07

iTrader: (10)

Dead ON!!!

Only thing I would add.....is that if you do not have your vats disabled then you will need to wait at least three minutes with the key off before you try your next resistor......or leave your key on and wait until your security light goes out........I believe this is correct, been a while since I worked with this but i am pretty sure that was how it worked. Good luck

wait4me

iTrader: (10)

Why worry about the bcm? Just shut off vats in the computer and be done with it.

As far as the ohms thing, it will only let you try 1-3 different ones before it locks down for 600 seconds. So it can be done but takes a while if you arent lucky.

A car stereo installation place that installs car starters will have those exact resistors.

Also the bcm will not report what setting it needs. That would be too easy for a thief to just plug in something and make the change.

Scoggin Dickey

iTrader: (34)

You can't scan it, trial and error only. Like stated above, it's easiest to just turn it off in the tune.

fast377

iTrader: (52)

If you just want the BCM for the keyless entry function, then do like stated above and have the VATS disabled in the tune. VATS has no bearing on keyless entry functions.

carfreak07

iTrader: (10)

Wont work!

Your key must match the vats module you ahve installed or it will not start....the two items are a pair.....when you disable the vats, it will allow the vehicel to run longer than three seconds if it will start. In this case the vehicle will not start because the two do not match. The keyless entry may work but he wont be able to drive it...lol he can show his friends he has installed keyless entry on it though, just hope they dont want a ride...ha ha. If he really has to have the keyless entry, he needs to mimic the correct resistance and then have a key cut. Hope this info helps him out.

I drove myself crazy with the similar problem....this is why i learned! I bought a car with a bad engine....brought it home and got it back together and had lost the only keys i had. I took the ignition out and tried to start with a ratchet and nothing, jumped the starter and it ran for 3 seconds (vats). Finally installed an ignition and bcm out of a 2000 SS and it fired right up with no issues....now i had no door key lol. I finally was able to drive it up for inspection since it was out of state and then I ordered trhe correct keys from gm and installed the factory bcm and ignition back in the car. Theres a whole other story to go along with this with another SS of mine but I wont go into detail with it.....faught it for over 2 years.....yea that is enought to make you want to burn the thing! lol anyway hope this info helps ya out man!

Scoggin Dickey

iTrader: (34)

He said to disable it in the tune, that will work. There is an option to simple turn VATS off. Then the key resistance won't matter and he can use his old keys.

PadreSmith

iTrader: (24)

I like the vats function for this exact reason. If someone wants to steal my ride then they need a pocket full of resistors and enough time to try each one. I definantly want to keep the vats. I also want the keyless entry function because I will have shaved door handles. The keyless function will trigger the solenoid to pop open. So I would like to keep both functions. Buying a bunch of resistors is probably the best option at this point. Thanks for all the help and posting the resistance values.

fast377

iTrader: (52)

Does your car have power locks? If it does, just buy an alarm...python or viper or something comparable. Save yourself the trouble.

wrencher

iTrader: (2)

I misread the first thread
I didnt think it was a F/Y body, it does have the pass key I system then.
You cannot determine the resistance value thru the module itself.
If you have the BCM's cars VIN # you can get the key code from a willing dealer. They should have the info available for what # resistor key it needs to be cut with.
To use the keyless entry feature if your car didn't come equipt you will still need a few more componets & mods to make it operate.
Not sure exactly, but I'd refer to the wiring diagrams & see what differs in the keyless/manual regular power lock cars.

carfreak07

iTrader: (10)

I had a 98 6cyl that had power locks and no keyless entry function, when I installed the bcm and ignition from a 2000 SS, the keyless entry worked, so I am assuming the only thing you need is power locks......when I hit the lock button, the lights lit and the horn beeped twice just like the SS....mighta been a fluke but this was my experience. When I went back to the original bcm and keys, I could not get the remotes to even program on the car....so i guess the main thing here is the bcm. Good luck getting your keyless entry.


PADRESMITH:
How much would a bcm and ignition and keys be worth? I may sell mine if your interested! I thought I was going to need for my SS but I found the problem before I installed!

PadreSmith

iTrader: (24)

PADRESMITH:
How much would a bcm and ignition and keys be worth? I may sell mine if your interested! I thought I was going to need for my SS but I found the problem before I installed![/QUOTE]

It would have to be less then the cost of 15 resistors. LOL!

PadreSmith

iTrader: (24)

Yea I reread my first post again and saw how you could have thought it was the passkey II. Thanks for the info everything helps.