Good day folks
I'm new here, asking for help and hoping to contribute what I know. I've never had any issues with my car so this is a first for me.

I have a '98 Firebird Formula, my key broke open and I lost the circuit board so I went to my dealer and asked for a new fob. When they got the first new one, the bcm wouldn't accept the program change so they ordered a second fob and the same thing happened. They told me I needed a new bcm but they are discontinued by GM.

I found another bcm online, the UPL is there, the Canada code and model are the same, the only differences are in the numbers under the barcode and the initials before the "09353691" numerals. My bcm code has a "GM: 09353691" code and the bcm I want to buy is from a 2001 Firebird with the code DE: 09353691, (as the seller says-picture of the bcm shows all numbers). Is this just a manufacture date code or does it stand for something important I need to take into consideration?

Is the barcode GM's part number associated with the vehicle it belongs to or something similar?

Any inut would be appreciated, thanks.

 

The VATS pellet in the key is tied to the BCM. So new BCM means new keys or VATS bypass unless you get a BCM that needs the same resistance in the pellet or it hasn't been programmed yet.

Also, its probably not an issue with the BCM anyway for key programming problem. Usually its someone not following the correct instructions or wrong key fob. Search on here and try the instructions yourself to see if you can get the fob programmed. If you still can't get it to work and you are sure its the correct fob, then maybe it is a problem with the BCM.

I can't help with part numbers though. However, from memory, the 98 model BCM may be different than the later ones.

Also, make sure you don't have an aftermarket alarm that bypasses the BCM's control of the door locks.

The Stereo & Electronics Section is a better area for this. I can move this there.

 

Hi, thanks for the quick reply. I don't have an aftermarket alarm on the car.

Since I'm a newbie at this, is the VATS pellet the circuit board in the fob or is it part of the circuit board in the fob?

The guy who's doing the work on my car is a GM dealer electrical & electronics specialist where I work, he also knows that the most likely problem with the bcm's in general are the 5 large solder points on the back of them. He mentioned and conformed my findings that one or more of those solder points may be bad. I've read this solder issue on a couple of different websites researching this and wondering the validity of that statement.

The seller will provide his old bcm with the matching remote if that's what you mean.

The other question I have is, is this just plug & play or is it something I need to have the dealer install & match to my car?

 

VATS = Vehicle Anti-Theft System. Its the built-in OEM security that GM used on some cars for several years. It uses the small black and silver looking "pellet" in the key blade itself. It is really just a resistor. If you are getting a used BCM, you need to know the resistance of the key so you can get matching keys (or do VATS bypass, but you still need to know the resistance).



The 5 solder points that make a "T" shape can fail. There are threads on here about it. Common symptoms are intermittent radio cutting out or windows intermittently not working. I'm not sure if it will cause an issue with key fobs, but if those solder points are cracked, fix them first and see if that fixes the issue.



Also, I don't remember if the Odometer is backed up in the PCM or BCM. It is stored in the Gauge Cluster and one of those others, but I forget which (probably PCM instead of BCM).

 

Got it, I know exactly what you're referring to, I've been calling it a program chip on the key.

Yes, that is one of the threads I read regarding the solder point issues.

Thank you very much for the advice, I appreciate your assistance and will follow up when I resolve this annoyance.

 

The bad solder points on the BCM board is a common issue but it relates only to the Retained Accessory Power (RAP) circuit which provides power to the radio and windows. It is not related in any way to the locks or keyless entry. As VIP1 mentioned, it certainly can't hurt to fix the solder joints if they need it but it won't have any effect on your fob programming.

Also as VIP1 suggested, please try programming the fob yourself before going for a replacement BCM. The programming procedure differs greatly between different GM models so I would never trust a so-called "specialist" when I could confirm something myself - there are far too many of them who don't know the differences between models, but think they do, so they never look up the actual instructions (we see it here all the time).

Here are the proven steps to program a fob:

This procedure has to be followed exactly or it will not work. For example, don't leave out step one just because you don't have the optional factory alarm - do it anyway.

 

Good evening VIP1 & WhiteBird00, sorry to take so long to post the results of my bcm/remote issues. I hope I explain this correctly since I don't know the proper terminology, if it doesn't seem right, please correct me.

So, after all is said & done, the bcm I bought second hand works fine, I have 2 complete sets of ignition keys and remotes - yeah team!!!
Here's the process that took place: I was told that during the programming process, new remotes would not be accepted by my existing bcm so I needed to find a second-hand unit (bcm's are discontinued by gm). The tech tried several new remotes with no luck using the 7-step process you outlined. The person I bought the bcm from also supplied me with one original remote. After installation and during the programming of the bcm, I was told there are 15 "spots" or VATS code positions that can contain the various ignition keys with corresponding remotes. My existing ignition key was not accepted by the new bcm because spot #13 was already pre-programed to the original key and could not be rewritten. I had them order 2 new keys that were coded for any VATS code except "13" & a new remote. Once they received the new keys coded for #15 and a new remote, everything got programmed and operated correctly. Back to 100%.

Considering I work for a gm dealer and got all the employee discounts, 3 hours of labour including the second hand bcm & remote, this whole thing cost about $600 CDN. It's what, about $10 bucks US? LOL It's $500 more than I wanted to spend but I have the piece of mind knowing I have 2 full sets of keys/remotes and a spare bcm (c/w my original key) which I can repair (hopefully), just in case. If I were just a guy off the street, guaranteed I would be paying over $1000.

Thank you for your input, teaching me some of the in's & out's of this issue and hopefully I don't have any more modules crash on me.
My next endeavor, see if I can find a set of 3.42 gears to replace the 2.73's for that weird-sized GU2 rear end without costing an arm & a leg in the process.

 

I'm glad you got everything working.

However, there are some things in your description that need some clarification (just for educational purposes and for other members who may read this thread). A brand new BCM programs itself to the first ignition key it sees and after that can never be reprogrammed - at least not without a major rebuild of the board. The thing it remembers is the resistance value of the pellet in the shaft of the ignition key. There are 15 different resistance values used by GM in their various cars although only 14 of those were ever used in f-bodies. A list of the actual resistance values is available in several posts in these forums if you really wanted to know what they are... they're used to get the correct resistors when bypassing VATS. The VATS key resistance value is unrelated to keyless entry remotes so there are no "corresponding" remotes for any keys.

When you buy a used BCM (rather than a rebuilt one which has been reset), it will already be programmed for one of those 14 resistance values and will only accept that value from the ignition key when trying to start the car. It's not that there are "spots" that are used and unavailable. It's just that the BCM sends electrical current through a wire to the ignition cylinder where it flows through the resistor pellet in the key and back through another wire to the BCM which then calculates the resistance it got through the key pellet. If the resistance matches its programmed value then it lets the car start. If it doesn't match then it turns on the SECURITY light in the instrument cluster, shuts off the fuel enable signal to the PCM, and disables the starter relay to prevent the car from starting. From the sounds of your description, you apparently had an original key that had the #13 resistor (7500 ohms) and it didn't match what the used BCM was expecting. That meant you needed a key with the correct resistance value that matched the used BCM. Considering you only knew that the #13 value didn't work, you got incredibly lucky that the first one you got happened to be the right value - you only had a 1 in 13 chance to get the right value out of the remaining possibilities so you probably should have bought lottery tickets or gone to a casino that day.

The remote had nothing to do with which VATS resistor was used but it did matter that the correct resistor was used (i.e. the one that matched the value stored in the BCM). That's because part of programming the remote is cycling the ignition on and off but the BCM won't go into programming mode if the ignition key used doesn't have the resistor value it needs. Now that you have the right (matching) ignition key, you can go back and program the other remotes that previously didn't work. You can program up to four of them (that's the limit the BCM imposes on total programmed remotes) so you'll have spares.

 

Thanks for the clarification WhiteBird00. Since I'm an electronics guy, I follow exactly what you're saying. This clears up the statement the tech told me that he had to order keys with a "#15 value" in order to be able to have the new keys work with the used bcm. I've been buying lottery tickets for years and I've spent a whole lot more than won! Needless to say, this last month hasn't been any different.

Ok, I'm not sure why the tech could not program the new remotes with my original bcm & key. I believe he told me that my original bcm would not go into programming mode when he tried to program the new remotes and that's why I needed a different bcm. When I brought it up, he said the 5 solder points on the board may have something to do with this issue. Anyway, everything works regardless and I can dig into my old bcm to see if there are any cold solder joints I could fix without fear of stranding my car.

The oem remote that I had was simply to lock & unlock the doors, open the rear hatch and an alarm button to sound the horn. These new remotes that the tech programmed in are also oem and do not have a remote start function, it's irrelevant to me anyway because I don't drive my bird in the winter. If I did, I would get something like a Compustar system.

Thanks again for everything, it's been quite a learning experience and I appreciate all your input & help. I'm not terminating the conversation, I'm just grateful and more than willing to learn about all this stuff, I just hope I never have to go through this again but share my experience if asked.

 

Ah ha... the tech ordering the #15 value key specifically, rather than as a random selection, takes the luck aspect out of it. He must have known that was the correct value either by having the key that came with the used BCM and measuring its resistance or by testing the various values until finding the correct one. There are VATS bypass boxes that do that - they have all 15 values wired to a rotary switch so all you have to do is connect the two VATS wires and rotate the switch to try each possible value until you get the one that works. A rheostat can do the same thing except that you'd have to measure the value at the rheostat terminals once you found a position that worked (instead of just reading the pre-labeled switch). That would explain why your lottery luck didn't change.

 

Yeah, I should be so lucky with that lottery thing! :-P Through our conversations and your teaching me, I figured there was method to his madness when he said he needed to order a key with a specific value, that's where that #15 came from. I had a feeling he was talking about the VATS resistor but did not realize how complicated it was until you explained it all to me. He didn't say how he came up with the value, whether it was the easy way or not. He did tell me it took him a while to find out what key value he needed to make everything work.

Cheers.