Having trouble with writing ,,supposed to get keys 6 bytes 4

[DWS]

Limp mode is more of a state than a mode. Like a GM computer, if it sees the engine coolant temp really high, it's right part of the tune to pull ignition timing. Toyota/Honda don't really have that. You can have a code set but have zero effect on how the car runs, P0420 is one for example that shouldn't effect the running of any car, it's just a test to validate that the cat is good and the secondary o2 sensor is reading that it's bad or the o2 sensor is bad.

No clue on the LS droid stuff, never used it. I do know HP Tuners works with a bunch of the P04 computers, but I think even they have some they don't cover yet. The BDM route in theory should work for all of them, but have to have the matching settings setup in the software for the flash chip involved and writing sometimes requires extra steps which is where the data sheet comes into play.

[antus]

lsdroid is supposed to do p04 but there are different years of p04 that are different so I cant say for sure. you could send the details of your pcm/operating systems as an enquiery when your looking to buy the xpro. Im still not sure if your problem is wrong pcm or wrong bcm. if its wrong bcm then turning off vats on the pcm might not be enough. also not sure how key security works on the us cars. If its like our aussie ones you may be needing some kind of learn between the pcm, bcm, key.

[DWS]

lsdroid is supposed to do p04 but there are different years of p04 that are different so I cant say for sure. you could send the details of your pcm/operating systems as an enquiery when your looking to buy the xpro. Im still not sure if your problem is wrong pcm or wrong bcm. if its wrong bcm then turning off vats on the pcm might not be enough. also not sure how key security works on the us cars. If its like our aussie ones you may be needing some kind of learn between the pcm, bcm, key.

I'm US based, not sure 100% how the BCM and PCM are linked, I've seen videos say they are VIN linked. For the key, they are just a resistor here, like 14 possible values. Here's a post I found showing them and the resistor values. I'm not sure how accurate the computer is for reading the resistance for spoofing. I've read the newer ones put the resistor in the ignition switch assembly instead of the key because of them having a lot of connection issues. Pretty sure eventually they went to the wireless RFID style like Toyota/Honda has been doing since 1998.

https://mcguirelocksmith.com/service-ar ... et-number/

Of course cars from different area's of the world have different computers and such, like in NZ I found out the Camry's there are JDM's and they can look like a no immo computer, but actually have it, but I don't have a pinout to match up to know which pins they are and such. Tempted to buy one of those computers just to poke at though to see how much is different. Of course different area's of the world have different emission standards too.

Anyway, would be interesting to hear what the security system is like over there in AU for these late 90's early 2000's GM's.

[antus]

When implemented in the key its the BCM that communicates with the key, and there is a challenge/response between the pcm and bcm, for the bcm to report its seen the key. When you turn off vats, on most cars the pcm no longer asks the bcm and everything is fine. On some models though there is additional security that locks out the starter, even if the pcm is heppy. This is in the 2000s though where I have seen it.

It might be possible to just turn off vats in this case, but I was just flagging that if the root cause is a new bcm, then there may be more too it. I expect you'd use a tech1 or tech2 to relearn the security and re-link the new bcm and the pcm. So if buying new equipment you'd want to get some confirmation that its going to work, first.

[DWS]

I see, makes sense starter cut relay needs to be active for starter to work possibly. Easy enough to wire past that though so not much of a "security" thing, just more being annoying you have to bypass it lol.

I see, I never used a Tech1/2 but I've seen them used in vids. Kind of funny trying to look at things from a stock car point of view instead of a stripped down bare min wiring demo derby car lol.

Anyway, not 100% sure what the OP's orig problem was that prompted them to start this thread, like it sounds like they can run their car with the replacement computer and I think BCM, just the scanner says SE instead of GT of my understanding. Either case, lot of interesting info ended up in this thread.

[DethRattles]

I bought the car and it had the famous gm security relearn process daily. Had to let the car sit for 10 min and the security light would go off. I put a resistor inline with the bcm and that fixed the car. Then the bcm started messing up, windows wouldn't roll down, trunk pops, doors chiming while closed and no key in. So i thought that i could install junkyard one,,,no crank,,,i then thought maybe it needed the resistor...no crank. I then got the matching pcm from the same junkyard car and she started. I then wanted to use my old gt pcm with a bit of tuning, figured i could disable vats and it would work in the car.

Pcmhammer then come into play, I also bought a tech2win and a vxdiad nano. Pcmhammer couldn't read my old gt pcm, and with the help of a lovely gentleman on this forum it did. Pcmhammer cant validate the vin nor can it write a p04. I then found out through the autoid on my scan tool that the junkyard lied to me about what vehicle the pcm/bcm come from and that it was an se model. So i really want my gt pcm in because i have an itchy feeling that theres different settings between the se and gt. I've learned that if i really want my gt pcm in that i'm gonna have to physically remove and swap the old bcm to the new eeprom chip(scary). If i mess up the soldering job then i'll have to buy either an 89$ bcm thats plug and play or a junkyard bcm/pcm from a gt and wont be even sure if their arent faulty.

The vats system (which i read i had passlock 2) reads the resistive code in the ignition cylinder Which the bcm then talks to the pcm. Vin does not matter because i switched the vin on my gt pcm on the bench and threw it in. The car wouldn't crank with the new vin matching the se vin. And the car auto id'd as an se still. The bcm seems to control all of what the car is. Now the vin may have something to do with the handshake process but gm says theres a password. Bcm sends the password to the pcm and allows the car to crank. They made these bcms a one time use and cant be programmed by a tech 2. I might be able to get the password from gm through their sps pass thru service on my tech 2 but the subscription is 40$ and might not work. I wanted to see if i could get pcm hammer to tune this gt file and flash it into the se pcm. This isnt going to happen anytime soon. I will contact obx and find out if my pcm is tuneable in a minute. It makes me jealous that these corvette owners are getting everything. Gm really messed up on my pcm. Theres a video of someguy showing he's able to reprogram his trucks bcm with the nano through sps service and his truck is a 2007.

Now the chip inside the bcm is unreadable on the board abut is able to be cloned off. Pontiac grand ams of the era had a tsb(technical service bulletin) that the vent under the wiper cowl leaks water into the passenger floor area. It so happens to leak right onto the connectors on the bcm. The fix is a dollar piece of foam installed. Since the bcm isnt sealed the water creeps into the bcm an wreaks havoc. Do you thing this was a purposely designed thing? There are so many people having to goto to the stealership and buy a brand new bcm since it couldnt be programmed.

i'm emailing obx, but i need money. Anyone in the market for a otc touch obd2 with bluetooth interface,subscription expired in 2016, its bidirectional touch screen ....270 shipped.

[DethRattles]

I bought the car and it had the famous gm security relearn process daily. Had to let the car sit for 10 min and the security light would go off. I put a resistor inline with the bcm and that fixed the car. Then the bcm started messing up, windows wouldn't roll down, trunk pops, doors chiming while closed and no key in. So i thought that i could install junkyard one,,,no crank,,,i then thought maybe it needed the resistor...no crank. I then got the matching pcm from the same junkyard car and she started. I then wanted to use my old gt pcm with a bit of tuning, figured i could disable vats and it would work in the car.

Pcmhammer then come into play, I also bought a tech2win and a vxdiad nano. Pcmhammer couldn't read my old gt pcm, and with the help of a lovely gentleman on this forum it did. Pcmhammer cant validate the vin nor can it write a p04. I then found out through the autoid on my scan tool that the junkyard lied to me about what vehicle the pcm/bcm come from and that it was an se model. So i really want my gt pcm in because i have an itchy feeling that theres different settings between the se and gt. I've learned that if i really want my gt pcm in that i'm gonna have to physically remove and swap the old bcm to the new eeprom chip(scary). If i mess up the soldering job then i'll have to buy either an 89$ bcm thats plug and play or a junkyard bcm/pcm from a gt and wont be even sure if their arent faulty.

The vats system (which i read i had passlock 2) reads the resistive code in the ignition cylinder Which the bcm then talks to the pcm. Vin does not matter because i switched the vin on my gt pcm on the bench and threw it in. The car wouldn't crank with the new vin matching the se vin. And the car auto id'd as an se still. The bcm seems to control all of what the car is. Now the vin may have something to do with the handshake process but gm says theres a password. Bcm sends the password to the pcm and allows the car to crank. They made these bcms a one time use and cant be programmed by a tech 2. I might be able to get the password from gm through their sps pass thru service on my tech 2 but the subscription is 40$ and might not work. I wanted to see if i could get pcm hammer to tune this gt file and flash it into the se pcm. This isnt going to happen anytime soon. I will contact obx and find out if my pcm is tuneable in a minute. It makes me jealous that these corvette owners are getting everything. Gm really messed up on my pcm. Theres a video of someguy showing he's able to reprogram his trucks bcm with the nano through sps service and his truck is a 2007.

Now the chip inside the bcm is unreadable on the board abut is able to be cloned off. Pontiac grand ams of the era had a tsb(technical service bulletin) that the vent under the wiper cowl leaks water into the passenger floor area. It so happens to leak right onto the connectors on the bcm. The fix is a dollar piece of foam installed. Since the bcm isnt sealed the water creeps into the bcm an wreaks havoc. Do you thing this was a purposely designed thing? There are so many people having to goto to the stealership and buy a brand new bcm since it couldnt be programmed.

i'm emailing obx, but i need money. Anyone in the market for a otc touch obd2 with bluetooth interface,subscription expired in 2016, its bidirectional touch screen ....270 shipped.

[MudDuck514]

snip
[06:14:22:043] VIN: 1G2NF52E74C111597

Just curious;

Is this the VIN from the CAR/Original PCM?
Or is this from the replacement PCM?

I ask because I have a document the lists the 4th and 5th characters of the VIN (Actually it list ALL of the positions)
as belonging to an "N-Body" Grand AM SE1 vehicle (NF)
4th is ALWAYS an N for the Grand AM
5th is
E for SE (NE)
F for SE1 (NF)
G for SE2 (NG)
V for GT1 (NV)
W for GT (NW)

Mike

[DWS]

There could be real minor tuning differences between the two, but since it's only 5hp more, it doesn't seem like it would be much of anything, if anything the computer you have in it now could make more hp with the larger intake/exhaust. 5hp is splitting hairs though, most dynos you're going to change a few hp at those levels since nothing is exactly the same and every run is slightly different. To give context, if it was 170hp for SE and 175hp for GT, that's a 3% difference. You'd probably never notice the difference driving it, if you race it, like 1/4 mile, I suspect you'd see the time differences then.

Also remember, the trans shift pattern and such are part of the computer too, so the GT could be sporting a bit more aggressive pattern to make it hold gears a little longer. Depending how you look at it, the SE might actually give you similar hp and better mpg under the same driving conditions.

Anyway, getting a BCM + PCM from a different junk yard and getting the one from the correct model should fix your worries on the GT vs SE, but technically it should be possible to copy the GT programming to the SE. The no crank issue sounds like BCM has to match the PCM, and when they do match it's good. Normally "passwords" are terms thrown around that just means a code both devices agree on which generally is the VIN number for GM's. For Toyota it's the raw key code, not encrypted or anything. It would be kind of interesting to check the tune GT vs SE but I suspect the numbers are very similar.

This makes me wonder if the 90's quad fours standard vs high output, if the computers were different at all, or if it was just physical changes, cams and intake I'm pretty sure are different on the HO version, probably larger exhaust too. I read up on swapping the parts over long ago but no one mentioned about needing the computer swap to get the full power.

[DethRattles]

snip
[06:14:22:043] VIN: 1G2NF52E74C111597

Just curious;

Is this the VIN from the CAR/Original PCM?
Or is this from the replacement PCM?

I ask because I have a document the lists the 4th and 5th characters of the VIN (Actually it list ALL of the positions)
as belonging to an "N-Body" Grand AM SE1 vehicle (NF)
4th is ALWAYS an N for the Grand AM
5th is
E for SE (NE)
F for SE1 (NF)
G for SE2 (NG)
V for GT1 (NV)
W for GT (NW)

Mike

My original gt pcm and vin for the car has a W,,,the vin you listed is from the se bcm/pcm