BCM Flash

[Wyked88]

ok guys, just stumbled onto these forums, so here i am, first time user. basically i’m having a hell of a time finding someone to flash my BCM (because having someone else do it is just so much more efficient)

alas, i’m pretty tech savvy, and have been doing tons of reading on how to do this myself, but i had a heart attack 2 weeks ago, and i just don’t have the focus or energy to read outdated & useless info any more.

so, here’s my current situation:

*i have an 08 Silverado 3500HD 6.6
*i fried the BCM
*bought replacement used BCM
*Have access to a Tech2 w/Candi module
*registered with ac delco/gm (thought i would do tech2-win) but

if you pretend like i’m a 6yo, and were to give me literally step-by-step instructions & tell me what hardware/software i might need to flash my own BCM i’m sure i could do it.

i couldn’t find any straight answers on the gm website, but it looked like if i paid for a 3 day access, and the single vehicle SPS fee, i could do it.

i’m willing to pay (what looks to be about $100) to do it legit.

anyway, any help would be greatly appreciated! TIA!

-Jeff

 

[mrrsm]

Not certain how you determined and condemned the BCM on a prior occasion, but unless you examined the system of the CAN-BUS with the Old OEM BCM still installed, perhaps following THESE step by steps for this Diagnostic might find that the BCM is still Okay and that the issue may involve a problem with the CAN-BUS or another Module instead.

THIS Video goes a long way (especially if Downloaded, Saved and Played back back at 3/4 Speed a few times) in showing HOW to Diagnose your CAN-BUS using a Basic Digital Multi-Meter FIRST and perhaps investigating the issue with the assistance of using a "BOB" (Break Out Box) as your BFF Tool Assist, too:

How to Use a Break Out Box:

 

[Wyked88]

i used years of tech experience, coupled with AllData diag procedures, and a snap-on scanner to determine that the bcm lost an internal ground.

per procedures (KOEO) testing across terminals (i believe it was) C & D on the brake switch connector, that there is no ground (provided by BCM) and when i touched test-light to the purple (ground) pin, the brake lights actually turn off.

issue is brake lights are constant on with key on.

if you have any other ideas, i’m open to hearing them.

 

[Wyked88]

i used years of tech experience, coupled with AllData diag procedures, and a snap-on scanner to determine that the bcm lost an internal ground.

per procedures (KOEO) testing across terminals (i believe it was) C & D on the brake switch connector, that there is no ground (provided by BCM) and when i touched test-light to the purple (ground) pin, the brake lights actually turn off.

issue is brake lights are constant on with key on.

if you have any other ideas, i’m open to hearing them.

also, when i fried my ECM (tapped the ECM to 12v+) i lost the internal ground. ECM had to be grounded externally for it to do anything, and then it had no CEL illumination, and no 12v charging. but the truck would run. so i got the ECM issue rectified, and now i have this BCM issue

 

[mrrsm]

For the pure preference of getting the BCM programmed to the in-dwelling PCM... My preference and experience would be to prepare a "Home Made" Bench Top Programming Harness that would isolate just the BCM and PCM along with a reliable Power Source and the Tech 2 connected to a "Home Made" DLC Connector and access the Tech2Win on-line ACDelco Site via a Legacy Laptop and download and install the Last, Best Silverado PCM Calibration (or even use the Disk Based SPS Programming) to re-program the New BCM to the PCM in a very simple Desk Top or Bench Top set-up:

Thread 'How To Install TIS2000 on an RCA Cambio Tablet with 32-Bit Windows 10'

Nov 5, 2019

How To Install TIS2000 on an RCA Cambio Tablet 10.1” with The Windows 10 (32) Bit Operating System:

UPDATE: Monday, September 16th, 2024 @ approx 6:ish EST:

THIS Site has apparently been obtained by another Corporation that no longer carries the Critical Step-By- Steps required to Activate the 16 Bit Features on the Windows 10 32 BIT (ONLY) necessary to KEEP THE ABILITY OF USING TIS2000 ALIVE IN THE WINDOWS 10 ENVIRONMENT;

DEAD PAGE:

http://techgenix.com/16-bit-applications-windows-10/

Instead... I have ventured elsewhere seeking to locate these critical steps and...

• mrrsm
• Replies: 5
• Forum: Tech 2

• 

This method eliminates ALL other Modules from confusing the CAN-BUS Communication occurring through your Custom Harness and Break-Out Box. I never had the occasion to set up such a rig for CAN-BUS... so it may involve the need of introducing a Short Pair of Twisted Wires with TWO Terminating 120 Ohm Resistors in your Rig... that can be picked up on the Break-Out Box at the #6 and #14 Pin-Outs to read "60 Ohms" when tested with your DMM.

If you follow along with the arrangements I actually created and documented in THIS Thread...perhaps some of these ideas can steer you in the right direction:

SOLVED! Thread 'How to Make A "GYMKO" Tech 2 Bench-Top Test Harness'

Feb 11, 2018

BIGGER EDIT: 04/24/2019

For THE BEST On Topic Solution ...Go Directly to Post # 42...

BIG EDIT:

This Thread originally was to cover creating a Test Harness to use exclusively for diagnosing and repairing the GM Trailblazer and Envoy, etc Instrument Panel Cluster and Components... but eventually it achieved a life of its own for Testing and Repairing ANY of the Many GM Modules... as long as they are added properly to the "GYMKO" Bench-Top Harness via the precise mirrored PCM and Harness Pin-Outs. More work needs to be done to take each of...

• mrrsm
• Replies: 58
• Forum: Tech 2

Example Harness Layout:

 

[Mooseman]

After ACDelco changed TDS to its current form, Tech 2 support was dropped and no longer works with TDS. There are supposedly other passthrough devices that can be used, like the Go-Diag GD101 or other J2534 passthrough.

If you do get a compatible passthrough, you should be able to buy a 2 year subscription for $40 USD ($59CAD) for one VIN. The 3 day thing is just for diagnostics access.

 

[Wyked88]

so, it turns out, that nowhere in the diagnostic flowchart/tree, is there a step which checks the Brake Switch itself. So after a $60 BCM, & $200 flash, it turns out that the brake switch itself was stuck (internally) in the “applied” position. $20 later and it’s fixed.

seems AllData steps SHOULD be:
A: check/Verify wiring OK
B: check/verify brake switch itself is OK
C: check/verify BCM is OK.

by SKIPPING ahead in the diagnostic chart, to a concern that wasn’t EXACTLY my problem, the issue would’ve been “short to 12v” … and i suppose while in my case this was TECHNICALLY correct, a step which included verifying the switch’s continuity itself would’ve SEVERELY minimized diagnosis time & costs involved in reaching the wrong conclusions.

 

[Mooseman]

So your original BCM was OK? Or do you mean that you need to check the brake switch function before programming a new one? What were the original symptoms that led you to a fried BCM? Enquiring minds want to know.

 

[Wyked88]

So your original BCM was OK? Or do you mean that you need to check the brake switch function before programming a new one? What were the original symptoms that led you to a fried BCM? Enquiring minds want to know.

long story short, yes, the BCM was good. the concern was brake lights illuminated at all times with key on.

first step on the diagnostic chart was to verify with scan tool “does signal switch from applied to released, and vice versa”

the answer was “NO”
this sends you to “brake lamp switch malfunction” diagnostic chart

1st step: unplug 4way connector at brake lamp switch. test for B+ between 12v TERMINAL C and ground.

Of circuit tests NORMAL replace BCM.

what it DOESNT do is have you continue the next 3 tests, which ALL conclude, if circuit tests NORMAL, replace BCM.

and then what it REALLY doesnt do is have you continue to step 5, which then indicates, if ALL circuits test NORMAL, CHECK or REPLACE Brake Lamp Switch.

what it ALSO doesn’t do is have you do a pin-out test on the brake lamp switch itself, to check for open/closed circuit internally in the switch, and which point i would’ve concluded, that the switch was stuck in the APPLIED position.

and it probably wouldn’t have gotten me, but in this case 2 1/2 weeks out of a major heart attack, im still suffering major brain fog & fatigue … and lack focus and the ability to concentrate. a perfect storm that led me to spend $300 (BCM & Flash) unnecessarily.

and the ONLY reason this seemed like the logical choice? i fried the ECM a while back, and it didn’t have this problem before doing that. so i just assumed i burned a ground or something in the BCM when i friend the internal ground in my ECM.

 

[Wyked88]

So your original BCM was OK? Or do you mean that you need to check the brake switch function before programming a new one? What were the original symptoms that led you to a fried BCM? Enquiring minds want to know.

not sure how the picture ended up upside down

 

[Mooseman]

Fixed it.

Talk about bad diagnostic instructions. Where did they come from? There are old GM-SI manuals available at https://charm.li/ but they are a little wieldly to find info at times.