Will a bad BCM keep the engine from running?
Thread Starter
Racer
Joined: May 2009
Posts: 263
Likes: 1
From: Andover KS
Will a bad BCM keep the engine from running?
I just finished installing a rebuilt LS1 in my 2000 C5 that went into shallow flooded street water and hydrolocked. The BCM got wet and when I took the cover off I found it has 2 burned Siemens creamic relays on the circuit board. My power windows, interior lights, hatch release, and cranking do not work, but everything else seems to work including power seats, HUD, gauges, etc. I cranked the engine over by crossing the starter lugs and it fires right up, but dies immediately. I was under the assumtion from previous threads that the PCM ran the engine. Would the fried BCM keep the engine from running? 
Melting Slicks
Joined: Mar 2001
Posts: 2,667
Likes: 849
From: New Jersey
The BCM must work properly for the engine to run (because the anti-theft function is performed by the BCM). You must get the correct replacement part-number BCM for your model-year, there are 2 or 3 different part-numbers used in the C5. It will have to be programmed by the dealer, using a Tech-2, to set the option codes and match the resistor-pellet value for the anti-theft system. Then the security password between the BCM and PCM has to be learned.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
There is an emergency BCM/PCM handshake procedure that you can use at home but it will not set any up any of the RPO codes that were in the old BCM. The TECH II has that capability. The procedure will allow the BCM to function with the PCM and the car will run.
I dont have the procedure at work.
BC
I dont have the procedure at work.
BC
Race Director
Joined: Aug 1999
Posts: 16,935
Likes: 26
From: Lackey, my own dragstrip VA.
Virginia Events Coordinator
Cruise-In IV Veteran
Cruise-In V Veteran
Cruise-In VI Veteran
Cruise-In VII Veteran
NCM Ambassador
My 97' had the BCM going bad............It would go into 4 cyl limp mode and a few other anoying things 
.
I could fix it by deleting the codes via the DIC. Once I turned off the car for a food/fuel stop, unbolt one lead on the battery for 30 seconds, reconnect and it would start. A new BCM did the trick as you can not reprogram a 97' BCM!
.I could fix it by deleting the codes via the DIC. Once I turned off the car for a food/fuel stop, unbolt one lead on the battery for 30 seconds, reconnect and it would start. A new BCM did the trick as you can not reprogram a 97' BCM!
Thread Starter
Racer
Joined: May 2009
Posts: 263
Likes: 1
From: Andover KS
Does anyone know what this handshake procedure is(below) so I can drive the car over to the dealership with a salvage yard BCM in lieu of the wrecker hauling it?
"There is an emergency BCM/PCM handshake procedure that you can use at home but it will not set any up any of the RPO codes that were in the old BCM. The TECH II has that capability. The procedure will allow the BCM to function with the PCM and the car will run."
"There is an emergency BCM/PCM handshake procedure that you can use at home but it will not set any up any of the RPO codes that were in the old BCM. The TECH II has that capability. The procedure will allow the BCM to function with the PCM and the car will run."
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Burning Brakes
Joined: Aug 2006
Posts: 1,217
Likes: 5
From: Stark County Ohio
Does anyone know what this handshake procedure is(below) so I can drive the car over to the dealership with a salvage yard BCM in lieu of the wrecker hauling it?
"There is an emergency BCM/PCM handshake procedure that you can use at home but it will not set any up any of the RPO codes that were in the old BCM. The TECH II has that capability. The procedure will allow the BCM to function with the PCM and the car will run."
"There is an emergency BCM/PCM handshake procedure that you can use at home but it will not set any up any of the RPO codes that were in the old BCM. The TECH II has that capability. The procedure will allow the BCM to function with the PCM and the car will run."
Turn the key to the "on" position, until the 'security' light goes out or quits alternately flashing between "Security" and "Battery". This relearn period always takes 10 minutes. How long does this take? 10 minutes. How long do I have to wait? 10 minutes.
After security light is no longer displayed, turn the key to the off position!
Wait 5-10 seconds and repeat the above procedure. two more times for a total of 3 start/relearn/attempts, remembering to shut the key off between each 10-minute relearn procedure.
This will take 30 minutes; no less.
If the car fails to start you did one relearn step (or all of them incorrectly).
If you left your headlamps on until the battery went dead and voltage dropped below 10.5 volts, no amount of relearn attempts will be learned!
P.S. Waiting a full 11-minutes instead of the “10-minutes” in the above procedure will insure better results – in other words you MUST allow at least 10-minutes to pass in each above procedure. (Waiting at least 10-minutes in required, but no sense in waiting 15-minutes for example)
EDIT - Options will have to be reprogramed into the replacement BCM with a "TECH 2".
Car will run and drive OK after the THREE 10-minute cycles are properly executed.
- Jim
Last edited by timemender; Jun 10, 2009 at 03:29 PM.
Burning Brakes
Joined: Aug 2006
Posts: 1,217
Likes: 5
From: Stark County Ohio
Car will run and drive OK after the THREE 10-minute cycles are properly executed.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Hereis what I have::
BCM/PCM RELEARN PROCEDURE
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. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer
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.
Bill Curlee
BCM/PCM RELEARN PROCEDURE
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. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer
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.
Bill Curlee
Burning Brakes
Joined: Aug 2006
Posts: 1,217
Likes: 5
From: Stark County Ohio
Hereis what I have::
BCM/PCM RELEARN PROCEDURE
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. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer
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.
Bill Curlee
BCM/PCM RELEARN PROCEDURE
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. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer
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.
Bill Curlee
However you laid out the proceedure in easy to read format. I should have left out all the stuff about the security light.
Thanks for jumping in to make the directions clear.
Bill - Does the key have to be "OFF" for 30-seconds as opposed to 10-seconds? Or is 30-seconds stated to insure that at least 10-seconds have passed?
-
Thread Starter
Racer
Joined: May 2009
Posts: 263
Likes: 1
From: Andover KS
OK, I have a salvage yard BCM on the way with the same service number. Hopefully it will be running soon so I can drive it to the dealership vs towing it. Thanks for the helpful information. Maybe I'll get lucky and the donor car had all of the same options mine has so I won't have to re-program it aside from the handshake method.
