Ccm
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,204
Likes: 4
From: Midland Georgia
St. Jude Donor '06
Ccm
I have a car that I am buying some parts off. The drivetrain is still good and the owner wants to retain anything related to the drivetrain so that he can crank the engine to show potential buyers that the engine starts and properly operates. I have been obtaining interior parts and the like. If I remove the CCM will the engine still crank and idle? Will remove the PKE have any ill effect on the car?
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,204
Likes: 4
From: Midland Georgia
St. Jude Donor '06
Melting Slicks
Joined: Jun 1999
Posts: 2,949
Likes: 23
From: Bowling Green KY
If you remove the PCM it definitely won't.
I'm not so sure about the CCM, there has to be away around it.
I know the Fbody cars have a different PCM but they do not have a CCM so obviously they run without one.
I've always been curious about this, maybe someone knows how to bypass this thing. I need to get rid of mine so somebody? anybody?
I'm not so sure about the CCM, there has to be away around it.
I know the Fbody cars have a different PCM but they do not have a CCM so obviously they run without one.
I've always been curious about this, maybe someone knows how to bypass this thing. I need to get rid of mine so somebody? anybody?
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
I can bring the CCM tech.
The CCM is part of the VATS system (and other stuff too). When the key is inserted and turned, the resistance of the pellet is checked. If it checks out, the CCM sends a byte string to the PCM saying all is good. Programming this out of the PCM is easy with tuning software. That will remove the CCM from the VATS equation (but there is more to removing VATS completely).
F-body PCM's are the same hardware, but programmed differently. F-bodies have a BCM instead (body control module). When the key is turned, a 50 hz square wave is sent to the PCM to signal everything is good and the PCM can allow the car to run. Note that the signal is different. While the CCM actually 'talks' to the PCM, the BCM only sends a square wave signal.
I don't have the wiring diagrams in front of me, but the CCM runs other stuff too, like the power windows (but don't quote me on that). If you want to remove the CCM, you really should consult a service manual because it handles a lot of functions (some of which may have to be re-wired to work without the CCM there).
The CCM is part of the VATS system (and other stuff too). When the key is inserted and turned, the resistance of the pellet is checked. If it checks out, the CCM sends a byte string to the PCM saying all is good. Programming this out of the PCM is easy with tuning software. That will remove the CCM from the VATS equation (but there is more to removing VATS completely).
F-body PCM's are the same hardware, but programmed differently. F-bodies have a BCM instead (body control module). When the key is turned, a 50 hz square wave is sent to the PCM to signal everything is good and the PCM can allow the car to run. Note that the signal is different. While the CCM actually 'talks' to the PCM, the BCM only sends a square wave signal.
I don't have the wiring diagrams in front of me, but the CCM runs other stuff too, like the power windows (but don't quote me on that). If you want to remove the CCM, you really should consult a service manual because it handles a lot of functions (some of which may have to be re-wired to work without the CCM there).
Le Mans Master
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Melting Slicks
Joined: Jun 1999
Posts: 2,949
Likes: 23
From: Bowling Green KY
I can bring the CCM tech.
The CCM is part of the VATS system (and other stuff too). When the key is inserted and turned, the resistance of the pellet is checked. If it checks out, the CCM sends a byte string to the PCM saying all is good. Programming this out of the PCM is easy with tuning software. That will remove the CCM from the VATS equation (but there is more to removing VATS completely).
F-body PCM's are the same hardware, but programmed differently. F-bodies have a BCM instead (body control module). When the key is turned, a 50 hz square wave is sent to the PCM to signal everything is good and the PCM can allow the car to run. Note that the signal is different. While the CCM actually 'talks' to the PCM, the BCM only sends a square wave signal.
I don't have the wiring diagrams in front of me, but the CCM runs other stuff too, like the power windows (but don't quote me on that). If you want to remove the CCM, you really should consult a service manual because it handles a lot of functions (some of which may have to be re-wired to work without the CCM there).
The CCM is part of the VATS system (and other stuff too). When the key is inserted and turned, the resistance of the pellet is checked. If it checks out, the CCM sends a byte string to the PCM saying all is good. Programming this out of the PCM is easy with tuning software. That will remove the CCM from the VATS equation (but there is more to removing VATS completely).
F-body PCM's are the same hardware, but programmed differently. F-bodies have a BCM instead (body control module). When the key is turned, a 50 hz square wave is sent to the PCM to signal everything is good and the PCM can allow the car to run. Note that the signal is different. While the CCM actually 'talks' to the PCM, the BCM only sends a square wave signal.
I don't have the wiring diagrams in front of me, but the CCM runs other stuff too, like the power windows (but don't quote me on that). If you want to remove the CCM, you really should consult a service manual because it handles a lot of functions (some of which may have to be re-wired to work without the CCM there).
But I don't remember seeing anything in Tunercat about CCM control, all I remember seeing is stuff on VATS, which I have turned off. I'll have to check again but I don't think there is anything there that specifically mentions the CCM.
GREAT info, thanks!
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
I'm actually going to rewire my car from scratch to do this very thing.
But I don't remember seeing anything in Tunercat about CCM control, all I remember seeing is stuff on VATS, which I have turned off. I'll have to check again but I don't think there is anything there that specifically mentions the CCM.
GREAT info, thanks!
But I don't remember seeing anything in Tunercat about CCM control, all I remember seeing is stuff on VATS, which I have turned off. I'll have to check again but I don't think there is anything there that specifically mentions the CCM.
GREAT info, thanks!
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Melting Slicks
Joined: Jun 1999
Posts: 2,949
Likes: 23
From: Bowling Green KY
I should know in a month or so whether it will fire up without the CCM so I'll try to remember to post a thread about it.
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
CCM interfaces with a lot of things;
Airbags for instance if it doesn't get the correct check for the airbag system it will not allow the car to start.A bad earth on a motion sensor is enough to fail the self check resulting in no CCM signal to the ECM.
Recall from my '90 FSM even interfaced with radio and A/c.
(Sold FSM so can't check actual details)
A F-body bin or chip is "supposed " to work with CCM delete so it might be able to be dialed out in TunerPro.
I bought a '90 with no keys; had VATS deleted on the chip , punched out the steering lock and it ran fine.
The moment I disconected the airbags (CCM still in place ) I had a no start.
Hotwire to the starter and it would spin over but no injector pulse.
Had spark; fuel in the TB and it would fire but not run
Airbags for instance if it doesn't get the correct check for the airbag system it will not allow the car to start.A bad earth on a motion sensor is enough to fail the self check resulting in no CCM signal to the ECM.
Recall from my '90 FSM even interfaced with radio and A/c.
(Sold FSM so can't check actual details)
A F-body bin or chip is "supposed " to work with CCM delete so it might be able to be dialed out in TunerPro.
I bought a '90 with no keys; had VATS deleted on the chip , punched out the steering lock and it ran fine.
The moment I disconected the airbags (CCM still in place ) I had a no start.
Hotwire to the starter and it would spin over but no injector pulse.
Had spark; fuel in the TB and it would fire but not run
Last edited by rodj; Feb 1, 2008 at 02:11 AM.
Melting Slicks
Joined: Jun 1999
Posts: 2,949
Likes: 23
From: Bowling Green KY
CCM interfaces with a lot of things;
Airbags for instance if it doesn't get the correct check for the airbag system it will not allow the car to start.A bad earth on a motion sensor is enough to fail the self check resulting in no CCM signal to the ECM.
Recall from my '90 FSM even interfaced with radio and A/c.
(Sold FSM so can't check actual details)
A F-body bin or chip is "supposed " to work with CCM delete so it might be able to be dialed out in TunerPro.
I bought a '90 with no keys; had VATS deleted on the chip , punched out the steering lock and it ran fine.
The moment I disconected the airbags (CCM still in place ) I had a no start.
Hotwire to the starter and it would spin over but no injector pulse.
Had spark; fuel in the TB and it would fire but not run
Airbags for instance if it doesn't get the correct check for the airbag system it will not allow the car to start.A bad earth on a motion sensor is enough to fail the self check resulting in no CCM signal to the ECM.
Recall from my '90 FSM even interfaced with radio and A/c.
(Sold FSM so can't check actual details)
A F-body bin or chip is "supposed " to work with CCM delete so it might be able to be dialed out in TunerPro.
I bought a '90 with no keys; had VATS deleted on the chip , punched out the steering lock and it ran fine.
The moment I disconected the airbags (CCM still in place ) I had a no start.
Hotwire to the starter and it would spin over but no injector pulse.
Had spark; fuel in the TB and it would fire but not run
Hmmm. On my 96' I disconnected both airbags and it ran fine. I also had an Fbody PCM at one time on the car and it worked fine as well with the CCM. So not even sure why the Fbody and Vettes have different PCM part #'s since they seem to work fine on either car (though I'm sure there is a good reason).
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Hmmm. On my 96' I disconnected both airbags and it ran fine. I also had an Fbody PCM at one time on the car and it worked fine as well with the CCM. So not even sure why the Fbody and Vettes have different PCM part #'s since they seem to work fine on either car (though I'm sure there is a good reason).
I swapped to OBDI, and the guy who programmed my OBDI PCM had some issues. When we put the f-body PCM into a C4, he could no get it to program. He ended up having to build a harness to bench tune it. After that, it would program fine.
Apparently the CCM/BCM vette/f-body differences make it not work.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
of the 90 -91 SD cars.
These two setups have physically different ECM's with different plugs and pinouts.
The Vette ECM has a dedicated link to the CCM (cranking fuel available ) whereas the F-body does not.
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
I bought a '90 with no keys; had VATS deleted on the chip , punched out the steering lock and it ran fine.
The moment I disconected the airbags (CCM still in place ) I had a no start.
Hotwire to the starter and it would spin over but no injector pulse.
Had spark; fuel in the TB and it would fire but not run
Looking at the schematics and connector overviews in the FSM, I don't see any input into the CCM for the air bag. It has a seat belt input, but no airbag/sir inputs.
I'm trying to fight through figuring out the wiring for a dash conversion, and I think only a very few circuits need to be operational for the CCM to work. If vats was deleted from the prom, I don't see why the ECM wouldn't run the car, unless the SIR system is inline with something else. But I don't think it's the CCM.
Now the DERM module has a energy reserve loop, will inflate airbags, record accident data, etc. It is also tied into the crank, as well as the ALDL data stream. I don't know of any way the ECM can be told not to pulse injectors via the data stream though..??
-- Joe
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Joe ,
Maybe it was the DERM hookup and not the CCM that caused the no start when I disconnected airbags.Sold 90 FSM when I stripped car for race use.
Maybe it was the DERM hookup and not the CCM that caused the no start when I disconnected airbags.Sold 90 FSM when I stripped car for race use.
Last edited by rodj; May 6, 2008 at 04:34 AM.
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
-- Joe
