BCM compatibility by years?
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From: Dahlgren Virginia
BCM compatibility by years?
Which year BCM's are compatible? From ebay it looks like 01-04 are, but I can't figure any other common years.
Do options have to be identical? E.g. if you have a notchback, will a bcm from a hatchback operate your trunk? I have active handling on my '99. Does the bcm control that and would the handling adjustments still work if I got one from a car without it?
Also if you get a used one, how do you match your key resistor value up to it to get your keys changed to what it wants to see? The dealer told me if I got a used bcm he couldn't program it.
Do options have to be identical? E.g. if you have a notchback, will a bcm from a hatchback operate your trunk? I have active handling on my '99. Does the bcm control that and would the handling adjustments still work if I got one from a car without it?
Also if you get a used one, how do you match your key resistor value up to it to get your keys changed to what it wants to see? The dealer told me if I got a used bcm he couldn't program it.
Drifting
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Joined: May 2006
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From: Dahlgren Virginia
Thanks, that does help. One other question: if you get a used bcm, how do you match your key resistor value to it? Do you still have to take your car to the dealer to get the key matched up if you got a used bcm?
I'm thinking of hooking a rheostat (variable resistor) up to the contacts and sweeping it with the ignition on until it starts. Thoughts?
I'm thinking of hooking a rheostat (variable resistor) up to the contacts and sweeping it with the ignition on until it starts. Thoughts?
Drifting
Joined: Jul 2007
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Thanks, that does help. One other question: if you get a used bcm, how do you match your key resistor value to it? Do you still have to take your car to the dealer to get the key matched up if you got a used bcm?
I'm thinking of hooking a rheostat (variable resistor) up to the contacts and sweeping it with the ignition on until it starts. Thoughts?
I'm thinking of hooking a rheostat (variable resistor) up to the contacts and sweeping it with the ignition on until it starts. Thoughts?
BCM/PCM RELEARN PROCEDURE
Start with a fully charged battery or you might drain the battery BEFORE the procedure is completed. It's long enough without having to start over.
You will need to conduct the PCM/BCM relearn process. This matches their handshake ID's and allows them to talk to each other.
Do this before you worry about VATS issues:
1. Turn on the key for 11 minutes.
2 Turn off the key for 30 seconds.
3. Repeat 1&2 two more times.
4. Turn on the key for 30 seconds.
The car should start and run with the new BCM.
This will sync the PCM to the New BCM but all of your RPO options will not be retained. You will need a TECH II to program them into the new BCM.
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From: Dahlgren Virginia
This site http://motorage.search-autoparts.com...09/article.pdf
says that when a TDM (theft deterrent module, which in our case is built into our BCM) is put in a car new, it reads the first resistance value it sees, and this resistance value cannot be reprogrammed. So I'll have to match the resistance value that's already in it.
They have a slightly different PCM BCM learning procedure. Yours is for a new BCM I'm assuming?
They say,
"If a new BCM is installed, it will learn the correct commands from the original PCM. However if either control unit was ever used in another vehicle, they must be reprogrammed together. There is a 30-minute programming procedure that does not require a scan tool.
1.Turn the ignition switch to START, then release it to the ON position (the engine will not start).
2. The “Security” light should be ON. After 10 minutes, it should turn OFF.
3.Turn the ignition switch OFF and after five seconds, repeat steps 1 and 2.
When this procedure has been done three times, turn the ignition switch OFF. The control units will exchange the correct commands during the next start-up attempt."
says that when a TDM (theft deterrent module, which in our case is built into our BCM) is put in a car new, it reads the first resistance value it sees, and this resistance value cannot be reprogrammed. So I'll have to match the resistance value that's already in it.
They have a slightly different PCM BCM learning procedure. Yours is for a new BCM I'm assuming?
They say,
"If a new BCM is installed, it will learn the correct commands from the original PCM. However if either control unit was ever used in another vehicle, they must be reprogrammed together. There is a 30-minute programming procedure that does not require a scan tool.
1.Turn the ignition switch to START, then release it to the ON position (the engine will not start).
2. The “Security” light should be ON. After 10 minutes, it should turn OFF.
3.Turn the ignition switch OFF and after five seconds, repeat steps 1 and 2.
When this procedure has been done three times, turn the ignition switch OFF. The control units will exchange the correct commands during the next start-up attempt."
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From: Dahlgren Virginia
Since yours is for a used BCM then I'll go with that. I just assumed the procedure you put up was for a new one since you said at the end that it would start, but it should not start with a used BCM since the key resistance value only has a 1 in 15 chance of being right. But I see that I missed a piece of logic since they say a new BCM will learn commands from the PCM you already had, or vice versa, so you wouldn't have to do any reprogramming procedure for a new BCM or PCM.
But yours DID start with a used BCM without matching the resistance value?! Either their article is wrong about the key resistance value not being able to be reprogrammed, or you got lucky and hit the 1 in 15 chance with the key you already had.
But yours DID start with a used BCM without matching the resistance value?! Either their article is wrong about the key resistance value not being able to be reprogrammed, or you got lucky and hit the 1 in 15 chance with the key you already had.
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Drifting
Joined: Jul 2007
Posts: 1,365
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Since yours is for a used BCM then I'll go with that. I just assumed the procedure you put up was for a new one since you said at the end that it would start, but it should not start with a used BCM since the key resistance value only has a 1 in 15 chance of being right. But I see that I missed a piece of logic since they say a new BCM will learn commands from the PCM you already had, or vice versa, so you wouldn't have to do any reprogramming procedure for a new BCM or PCM.
But yours DID start with a used BCM without matching the resistance value?! Either their article is wrong about the key resistance value not being able to be reprogrammed, or you got lucky and hit the 1 in 15 chance with the key you already had.
But yours DID start with a used BCM without matching the resistance value?! Either their article is wrong about the key resistance value not being able to be reprogrammed, or you got lucky and hit the 1 in 15 chance with the key you already had.
It was a used BCM from Vettenuts who is a supporting vendor on here.
