Instrument Cluster Changes '99-'04

[AaronGTR]

Originally Posted by datashifter

I have one of those ELM327 Bluetooth modules and have been using the Torque android app to scan my car for error codes for a couple of years. Admittedly I was happy enough with this and never needed/wanted/thought to crack open a terminal session with it. Upon doing a little reading about OBDC II, you are right about the command set being akin to the Hayes AT modem commands from back in the day. Might have to drag the hacktop to the car a little later and see if I can strike up a friendly conversation with the BCM via Bluetooth. I'm curious if there is a "programming fuse" in the BCM which gets blown after the VIN is set, or if GM's TECHII is simply saying "nah dude, I ain't gonna let you do that."

I should be able to shed a little light on that for you. To my knowledge, the VIN is not even stored in the BCM. If it is, there definitely isn't a fuse that sets it permanently. It is stored in the PCM and can changed with a tuner (or a Tech2) if the PCM is changed. If it's in the BCM as well, then it is also reprogrammable, and doesn't care if it matches the other modules. They had to do this and make it programmable because BCM's and PCM's occasionally go bad and have to be replaced.

I got a second PCM for my car because I was doing so many reflashes back in the day when I was doing a lot of tuning, and there is always a possibility of an error during a flash and brain-deading a controller. I wanted a backup PCM with my BIN file and VIN on it.

[The_Maniac]

Originally Posted by AaronGTR

To my knowledge, the VIN is not even stored in the BCM. .... It is stored in the PCM and can changed with a tuner (or a Tech2) if the PCM is changed. If it's in the BCM as well, then it is also reprogrammable, and doesn't care if it matches the other modules. They had to do this and make it programmable because BCM's and PCM's occasionally go bad and have to be replaced.

I have access to a TechII (and been playing with it as part of this quest to get the TIM system working) and the GM shop manual. The BCM does contain the VIN (I believe it has part to do with PassLock and I also suspect it may help to prove again people using chop-shop parts).
From what I found, it appears the base programming (which includes the VIN) for the BCM is flashed to a PROM that is a one time write, not controlled by a fuse (it's much like the ECUs in cars from the 80's used a chip, those chips could not be re-flashed). After the base programming is done to the BCM, the TechII reports that it is in "Secured Mode". So I can't take a BCM from a Grand Am and try and run it in an Impala, as I can't re-flash the base program. The shop book actually states if the programming is incorrect and the TechII reports that it's in "Secured Mode" (which means that one time write was completed, regardless if it was successful or not), it states you need to replace the BCM.
Now, in theory, perhaps that part of the BCM can be cleared and re-flashed but GM does not allow the TechII to do it. If so, then it would take some programming knowledge to determine how to read/write to that part of the BCM.

The PCM is 100% re-programmable. I have done it a bunch with my DHP PowrTuner. The PCM also contains the VIN, like you mentioned, you can re-program the VIN on the PCM, again, I believe this is part of PassLock. Plus I know when swapping PCMs, even with the VIN correctly programmed, you have to go through the security re-learn process (I believe that is so the PCM, BCM and PassLock chip on the lock cylinder are sharing the same internal password, I recall seeing something about that in the shop book).

This quest is getting into a lot of tech I don't yet know how to communicate with in the car. Plus, I am still not sure which of the modules are affected by this to make it work.

[datashifter]

Useful information, AaronGTR. Thanks!

Seems like it may be time for me to get my grubby paws on a spare BCM and open it for inspection. PROM chips can be replaced, after all.

On the IPC end, I ohmed out the EEPROM pins to pogo pin pads. Seems that three EEPROM pins are tied to a single pogo pin pad. As the EEPROM datasheet is not in the public domain, this could get interesting...

Makes me happy to have a few new projects though!

As for the BCM containing the VIN, I understand this is used primarily for the TheftLock of the newer radios without unlock codes and has nothing to do with PassLock, the ignition switch anti theft system.

[AaronGTR]

Yeah, there's a lot about the communications in these cars I still don't understand and am still learning too. I'm taking digital electronics basics in school right now, and I use CAN communications at work all the time, but I don't much about the CAN networks in the new cars these days.

[ecortech]

On my 2003 gt I bricked my BCM.
Part way through an update lost power to Tech2, fuse popped.
After fixing the fuse problem, when attempting to update Tech2 would report the BCM was locked, no go, no how.
Great need a new BCM.
While waiting for the new one to arrive, did some thinking.
If the BCM can be updated got to be a way to fix this.
So hooked up the tech2 told it I was replacing the BCM.
When it said to remove the old and connect new BCM, I just left the old connected.
Told Tech2 yep ok new installed ready to go.
Tech2 among several other things asks for vin.
Tech2 then goes merrily on programming the BCM.
When done all is good car fires up fine no problem at all.
Several options had to be turned on enabled etc...
I think I had to do a security relearn just as if I had a new BCM.
New BCM is in the cupboard unused waiting for the day it will be needed.
Old BCM still in the car running fine.
Old BCM supposedly locked unprogrammable now works.
When you tell Tech2 new BCM is installed it does not check anything just blindly writes file to chip.

Ed

[datashifter]

Very interesting, ecortech. Very interesting indeed...

Now I really wish I had a Tech2. Price is a bit prohibitive though.

AaronGTR, I don't think we have a CAN bus in our cars. I think it's GM-centric protocol for the 99-05 GA's/Alero's. Same basic principle, just a different protocol. Anyone may correct me if I'm wrong, and I encourage corrections!

[Madness10]

Originally Posted by datashifter

Very interesting, ecortech. Very interesting indeed...

Now I really wish I had a Tech2. Price is a bit prohibitive though.

AaronGTR, I don't think we have a CAN bus in our cars. I think it's GM-centric protocol for the 99-05 GA's/Alero's. Same basic principle, just a different protocol. Anyone may correct me if I'm wrong, and I encourage corrections!

Yes you are right, we do have the standard GM protocol. Take a look at this site. Scroll down bout 1/2 way and look at the bus styles. https://en.wikipedia.org/wiki/On-board_diagnostics and this site shows all the mnfr's protocols. http://www.alpha-bid.com/media/Share..._protocols.pdf

[The_Maniac]

Originally Posted by AaronGTR

Yeah, there's a lot about the communications in these cars I still don't understand and am still learning too. I'm taking digital electronics basics in school right now, and I use CAN communications at work all the time, but I don't much about the CAN networks in the new cars these days.

I'm really wishing I new more on the topic for this. Such as can I use the ELM Bluetooth adapter and a terminal program to copy the BCM software out to a BIN file. Even if I could, how do I hack the BIN file? I could use a HEX Editor, but you need to know what to HEX edit....

Originally Posted by ecortech

Old BCM supposedly locked unprogrammable now works.
When you tell Tech2 new BCM is installed it does not check anything just blindly writes file to chip.

Weird, I tried to do just that with the TechII I have access to and it calls me out, claiming it can't do it, the BCM is Secured.
My thought is if I can re-program my BCM as an '02 Alero, might the TIM system be available at that point.

Originally Posted by datashifter

I don't think we have a CAN bus in our cars. I think it's GM-centric protocol for the 99-05 GA's/Alero's.

In some of what I read, CAN is used generically, meaning "Car Area Network". So, yeah, we don't run the CAN bus protocol, but we do have a CAN system.
Terms, they can drive ya crazy !

[ecortech]

[quote=The_Maniac;1264127]I'm really wishing I new more on the topic for this. Such as can I use the ELM Bluetooth adapter and a terminal program to copy the BCM software out to a BIN file. Even if I could, how do I hack the BIN file? I could use a HEX Editor, but you need to know what to HEX edit....

I don't think the ELM327 will do what you want.
The ELM is very basic and limited command set.
I think what you need is a J2534 capable device.
J2534 protocol allows bi-directional control

Weird, I tried to do just that with the TechII I have access to and it calls me out, claiming it can't do it, the BCM is Secured.
My thought is if I can re-program my BCM as an '02 Alero, might the TIM system be available at that point.

I'm sure mine said locked not secured, yours is saying it's secured.
Gm has a security system so that only authorized technicians can access some functions. The tech2 unit has to be connected to pc with gm Service Programming Software to authorize security access.
I'm wondering if it may be just needing to enable the TIM option with Tech2 in new BCM setup. Once you have security access you should be able to enable-disable options. ie. if keyless entry option is disabled it will not work even though all the hardware is present on the vehicle, enabling the option will allow it to work.

Ed

[AaronGTR]

Originally Posted by datashifter

Very interesting, ecortech. Very interesting indeed...

Now I really wish I had a Tech2. Price is a bit prohibitive though.

AaronGTR, I don't think we have a CAN bus in our cars. I think it's GM-centric protocol for the 99-05 GA's/Alero's. Same basic principle, just a different protocol. Anyone may correct me if I'm wrong, and I encourage corrections!

Yeah, I know that. I was just stating that there are a lot of things with in-vehicle systems communications I'm still learning. The 99-05 n-body used serial data link communications for most module to module interfacing. They started using CAN-BUS on the G6.

[datashifter]

Originally Posted by AaronGTR

Yeah, I know that. I was just stating that there are a lot of things with in-vehicle systems communications I'm still learning. The 99-05 n-body used serial data link communications for most module to module interfacing. They started using CAN-BUS on the G6.

Roger that. Not having CAN-BUS makes me one happy panda.

On the IPC hacking front, progress is being made. I've managed to get BIN dumps from the ATMEL chip. Next up, soldering the daughter board back to the IPC and hooking it up in my car to get a mileage reading so I will know what values to look for as I hash through the BIN dumps.

I took many dumps (hehehe) using a multitude of chipset profiles as the ATMEL chipset is "custom" and the datasheet is not in the public domain. One of those dumps has got to be good (rofl)!

[ecortech]

No reason not to own a Tech2 these days.
You can get a clone for around $300.
They are basically obsolete from GM now.
Many of the better scan tools are in the same price range, but don't come even close to the capabilities of a Tech2.
I know many service shops have both and they function in every way just as good as an genuine GM tech2.
Much has been written about the clones, most if not all the problems with the early clones are known and have been corrected.
Do a bit of research, google Tech2 clone, find a reputable vendor that others have bought from.
Even if you have a problem parts are available and most problems are easily fixed.
I have used both a genuine GM tech2 and a clone.
I bought a clone from China just to see what it was like I was curious.
It was here in I think 4 days from China.
It has worked just fine, for more than 2yrs, has done everything I have needed.
Actually sold my genuine Tech2 and only have a clone now.
I have a number other scan tools, hand held, pc based, smart phone bluetooth etc..
which have cost me far more than the clone tech2.

Ed

[pongagt]

I just bought a clone Tech2 with a gm memory card and candi adapter for $276 from a seller on aliexpress. It had free dhl express shipping from china so it arrived in a couple days. I set up a old dell laptop with a serial port and now i can flash pcm's and do all sorts of fun stuff. I also bought a saab card so i could update my brother's car and change his dealer options.

[AaronGTR]

Sounds like what I need. I've wanted a tech2 or similar scan tool for a long time now. I never got around to actually looking into it and buying one because for a long time I could just read/clear codes with my power tuner (along with tuning of course), so I never bothered. It would still be useful to have though, and now my tuner isn't working anymore, so I need a functioning code reader.

Still thinking of getting one of those plug in blue tooth readers off amazon though just so I have something small and portable in my car that works with my smart phone, rather than having to tote along a laptop or other large diagnostic tool.

[Madness10]

Originally Posted by ecortech

No reason not to own a Tech2 these days.
You can get a clone for around $300.
They are basically obsolete from GM now.
Many of the better scan tools are in the same price range, but don't come even close to the capabilities of a Tech2.
I know many service shops have both and they function in every way just as good as an genuine GM tech2.
Much has been written about the clones, most if not all the problems with the early clones are known and have been corrected.
Do a bit of research, google Tech2 clone, find a reputable vendor that others have bought from.
Even if you have a problem parts are available and most problems are easily fixed.
I have used both a genuine GM tech2 and a clone.
I bought a clone from China just to see what it was like I was curious.
It was here in I think 4 days from China.
It has worked just fine, for more than 2yrs, has done everything I have needed.
Actually sold my genuine Tech2 and only have a clone now.
I have a number other scan tools, hand held, pc based, smart phone bluetooth etc..
which have cost me far more than the clone tech2.

Ed

Don't you have to be a license tech to buy the modules. I know anyone can but the Tech2 scanner clone, but what about the modules. Also, do the modules come with all GM cars programmed already?

[ecortech]

Originally Posted by Madness10

Don't you have to be a license tech to buy the modules. I know anyone can but the Tech2 scanner clone, but what about the modules. Also, do the modules come with all GM cars programmed already?

The clones come with whatever card you want, usually need to tell them which one you want. Everything you need is on the card.
There is usually a couple of cd's with the manuals and pc software TIS2000 that is used with the tech2 they also provide a dongle work around.

Ed

[ecortech]

Originally Posted by AaronGTR

Sounds like what I need. I've wanted a tech2 or similar scan tool for a long time now. I never got around to actually looking into it and buying one because for a long time I could just read/clear codes with my power tuner (along with tuning of course), so I never bothered. It would still be useful to have though, and now my tuner isn't working anymore, so I need a functioning code reader.

Still thinking of getting one of those plug in blue tooth readers off amazon though just so I have something small and portable in my car that works with my smart phone, rather than having to tote along a laptop or other large diagnostic tool.

The plug in bluetooth reader is very handy to have, I keep mine in my truck.
I ordered mine direct from China, I think it was $7 under $10 anyway, first one didn't work so ordered another from a different seller, it works fine. The one I have is the blue Vgate, works good with Torque Android app. Very quick and handy to retrieve codes reset the mil light, read live data etc.. prob as capable as any of the handheld scanners. Sure can't beat the price for what it will do.

If you are doing any mods/tuning one of the tuning programs such as the power tuner is best.


Ed

[The_Maniac]

The TechII I use is a clone as well (but the guy who got it compared it to a legit TechII a friend of his uses at a dealership shop, can't tell the difference).
It supports vehicles up to either 2013 or 2014, after that, it stops, period, as GM moved to the MDI setup and a subscription base.

My friend did not get the dongle to use the software on a laptop for flashing PCMs. When he asked my opinion, I looked at it and from what I could tell, it only did a small fraction of cars (PCM flashing via that config ended in like 2005 I think, after that, you needed to have a subscription I believe with TIS2WEB to get and use the PCM flashing functions on newer cars). But, it has all the other functions, such as updating the BCM (pending you have a blank BCM).

So far, it seems like money well spent. He's bought other tools over the years with claims that "sound" like a TechII only to be let down in the end. His clone was $300-$400, came with all the cables, CANdi module, carry case, the works.

[datashifter]

Upon looking at the clone TechII's (sadly I was unaware they existed) I have to say that I'm interested...after the next paycheck I might make the jump. Won't help me with the odometer, but I should then be able to program my own key fobs, muck with optional settings and other stuff I refuse to pay a stealership to do.

About the odometer though...I believe I finally have that angle figured out.

[ecortech]

If you do purchase a clone, and plan on programming keys, key fobs flashing BCM etc..
you will need the security dongle. Ask them if it is included, it may not be.
It's only about $10 for the dongle, not actually a physical dongle.
Just a software file, no dongle to misplace, they give you the instructions on how to use it.

Ed