Bcm

[LETZRIDE]

What is involved in me buying another BCM...I cant stand mine anymore...my radio is flickering on and off when I hit bumps in the road and it is not going away like it used to in previous years...So I believe it is time I got a new one...I have been thinking of getting a used one that is working off of ebay for 100$ or so...or possibly a new one for 200$ something...what do I need to know as far as tuning it in there so that the car starts up and doesnt lock me out, and as far as vats goes?

[phoenix_rising]

Re: Bcm

I also need info on this please for a 2000 Pontiac Grand Am. Thnx.

[bigbrian442]

Re: Bcm

If it is a new F body BCM they learn the ohm value of the first key inserted into the ignition. Once a key has been inserted, the ohm value the BCM wants can not be changed. The chip in the key is what has the ohm value.

If you plan to use a used BCM then you must have your key recut with the correct chip for the BCM you are installing. Two ways to find out what ohm value the BCM wants;

1 Have a key from the car the BCM is out of and read it with an ohm meter.

2 If you don't know anyone at a dealer, Buy the VATS bypass modules and plug each one into the VATS harness under the steering coulum untill the car starts. Then have your key recut with the right ohm value in the chip.

The number key and corresponding ohm values follow.

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

Also if your buying a used BCM and you have keyless entry you need to get one from another car with keyless entry. My car did not have keyless entry or the factory alarm until I put a BCM from a 02 SS Camaro that did have that stuff in it. Then all I needed were the remotes ,a shock sensor and a relay to make the lights flash when you armed the alarm. Everything was plug and play.

There is a big difference in passlock on the 2000 Grand AM and VATS on the 4th gen F body.

[flamingchicken]

Re: Bcm

like a damn encyclopedia

[LETZRIDE]

Re: Bcm

ok...to save headaches and confusion, Ebay has brand new ones for 175$...so If I grab that...I plug it into my car...I insert my key to start the car...it reads what ohm my key is, and everything will work fine?

I thought there was something about I have to do a write entire to the pcm to make it all work? otherwise they wont talk to each other and it will think I am trying to steal my own car...


Also, my car is the basic of all basic cars...no power anything...but I do have an aftermarket alarm system and remote starter wired in there...how will that effect the bcm or the new bcm I should say? Should anything be wired to it?

[bigbrian442]

Re: Bcm

When I changed my BCM I did not have to do anything to the PCM. Just plugged the BCM in found the ohm value of the key it wanted and everything worked. Added the shock sensor and relay for the lights at a later date.

Just inserting your key is the way it is supposed to work.... Never installed a new one.

Aftermarket alarms can be a PITA and could be the cause off your problems.

[LETZRIDE]

Re: Bcm

possibly...my alarm system pretty much doesnt even work anymore...except for when it is armed you cant start the car...that still works...the light flashes, and siren dont...

Remote start still works to...

Im pretty sure it is the bcm though because I can hear a clicking coming from the passenger side dash when the radio goes off and comes back on...plus it has gotten to the point now where if I want to just listen to the radio with the car off...when I turn the key backwards I get a "ding" and a security light flash and no radio...do it again and I get a "Ding, ding" two security light flashes and nothing...so I have to fight with it sometimes...