CCM codes help?!
Thread Starter
Pro
Joined: Dec 2004
Posts: 590
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From: Fairfield CT
CCM codes help?!
My '94 LT1, 6SPD w/90K miles is showing codes:
C 31/33/35/37
When I clear the codes they come back, and, of course along with the history codes.
The User's Manual for the grounding plug diag kit I have states these indicate:
data circuit shorted to B pos or CCM drive open (C31)
data clock circuit shorted to B pos or CCM drive open (C33)
data strobe circuit shorted to B pos or CCM drive open (C35)
M clock circuit shorted to B pos or CCM drive open (C37).
So what does this mean to a knuckle dragger like me and what can I expect when I access the CCM, and how the heck do I fix it? Could this indicate a loose/bad connection where ever this B pos thingie is, CCM drive thingie, or does the CCM need to be replaced.
My Heims was pretty clear that the CCM itself rarely fails and that loose/bad connections are the usual suspects. I have had an occasional, sporadic flickering of the dash/speedo lights leading up to this and it's still there.
Thoughts, ideas, opinions? Help!
Thanks,
Carl
C 31/33/35/37
When I clear the codes they come back, and, of course along with the history codes.
The User's Manual for the grounding plug diag kit I have states these indicate:
data circuit shorted to B pos or CCM drive open (C31)
data clock circuit shorted to B pos or CCM drive open (C33)
data strobe circuit shorted to B pos or CCM drive open (C35)
M clock circuit shorted to B pos or CCM drive open (C37).
So what does this mean to a knuckle dragger like me and what can I expect when I access the CCM, and how the heck do I fix it? Could this indicate a loose/bad connection where ever this B pos thingie is, CCM drive thingie, or does the CCM need to be replaced.
My Heims was pretty clear that the CCM itself rarely fails and that loose/bad connections are the usual suspects. I have had an occasional, sporadic flickering of the dash/speedo lights leading up to this and it's still there.
Thoughts, ideas, opinions? Help!
Thanks,
Carl
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
My '94 LT1, 6SPD w/90K miles is showing codes:
C 31/33/35/37
When I clear the codes they come back, and, of course along with the history codes.
The User's Manual for the grounding plug diag kit I have states these indicate:
data circuit shorted to B pos or CCM drive open (C31)
data clock circuit shorted to B pos or CCM drive open (C33)
data strobe circuit shorted to B pos or CCM drive open (C35)
M clock circuit shorted to B pos or CCM drive open (C37).
So what does this mean to a knuckle dragger like me and what can I expect when I access the CCM, and how the heck do I fix it? Could this indicate a loose/bad connection where ever this B pos thingie is, CCM drive thingie, or does the CCM need to be replaced.
My Heims was pretty clear that the CCM itself rarely fails and that loose/bad connections are the usual suspects. I have had an occasional, sporadic flickering of the dash/speedo lights leading up to this and it's still there.
Thoughts, ideas, opinions? Help!
Thanks,
Carl
C 31/33/35/37
When I clear the codes they come back, and, of course along with the history codes.
The User's Manual for the grounding plug diag kit I have states these indicate:
data circuit shorted to B pos or CCM drive open (C31)
data clock circuit shorted to B pos or CCM drive open (C33)
data strobe circuit shorted to B pos or CCM drive open (C35)
M clock circuit shorted to B pos or CCM drive open (C37).
So what does this mean to a knuckle dragger like me and what can I expect when I access the CCM, and how the heck do I fix it? Could this indicate a loose/bad connection where ever this B pos thingie is, CCM drive thingie, or does the CCM need to be replaced.
My Heims was pretty clear that the CCM itself rarely fails and that loose/bad connections are the usual suspects. I have had an occasional, sporadic flickering of the dash/speedo lights leading up to this and it's still there.
Thoughts, ideas, opinions? Help!
Thanks,
Carl
This is probably going to be a bitch to track down.
I'd start diagnosis from the cluster end rather than the CCM. Much easier to get to.
This "B pos thingy" is 12V.
[edit]Actually, I just checked this in the FSM, and the diagnostic charts for these DTCs tell you to diagnose from the cluster end. Just follow those charts.[/edit]
Thread Starter
Pro
Joined: Dec 2004
Posts: 590
Likes: 2
From: Fairfield CT
This is probably going to be a bitch to track down.
I'd start diagnosis from the cluster end rather than the CCM. Much easier to get to.
This "B pos thingy" is 12V.
[edit]Actually, I just checked this in the FSM, and the diagnostic charts for these DTCs tell you to diagnose from the cluster end. Just follow those charts.[/edit]
I'd start diagnosis from the cluster end rather than the CCM. Much easier to get to.
This "B pos thingy" is 12V.
[edit]Actually, I just checked this in the FSM, and the diagnostic charts for these DTCs tell you to diagnose from the cluster end. Just follow those charts.[/edit]
Thread Starter
Pro
Joined: Dec 2004
Posts: 590
Likes: 2
From: Fairfield CT
Gremlins in CCM!!!!???
This problem seems to be intermitent I haven't been able to work on this problem due to my traveling. Yesterday, I checked for the codes, - none, took the car for a long ride and checked again - got the history codes, cleared them and got C12. What gives?
Does this sound like a loose connector or the CCM giving up the ghost?
We're moving and I will be taking it on a 2,500 mile trip. Can I let this go? I need to spend the time packing up our stuff and might be forced to take it our for service.
Does this sound like a loose connector or the CCM giving up the ghost?
We're moving and I will be taking it on a 2,500 mile trip. Can I let this go? I need to spend the time packing up our stuff and might be forced to take it our for service.
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
Sorry I can't answer your question directly, troop, 'cause I dunno.
FWIW, yes, IMO it sounds like a loose plug somewhere - finding it
will be a PITA - due to where GM chose to mount the components.
Can you drive it a long distance as is? If it were mine, I'd probably
go ahead and make the trip. Generally, GM builds-in a lot of safety
features when they design a car - if a non-citical component (like the
CCM) fails, it will NOT shut the car down. You might loose the display
in the dash, but the engine will still run.
That's my opinion, based on my ECM test bench - I have a couple of
older Corvette ECMs that run on my work bench without being
connected to a CCM - and they run happily all day without knowing
the difference. I use them to look at software projects before I try
them in the actual car...
Does that guarantee I'm right about your car? No, but if I'm wrong
your money will be cheerfully refunded
.
Good luck with the trip. Heading back east?
DrJ
FWIW, yes, IMO it sounds like a loose plug somewhere - finding it
will be a PITA - due to where GM chose to mount the components.
Can you drive it a long distance as is? If it were mine, I'd probably
go ahead and make the trip. Generally, GM builds-in a lot of safety
features when they design a car - if a non-citical component (like the
CCM) fails, it will NOT shut the car down. You might loose the display
in the dash, but the engine will still run.
That's my opinion, based on my ECM test bench - I have a couple of
older Corvette ECMs that run on my work bench without being
connected to a CCM - and they run happily all day without knowing
the difference. I use them to look at software projects before I try
them in the actual car...
Does that guarantee I'm right about your car? No, but if I'm wrong
your money will be cheerfully refunded
. Good luck with the trip. Heading back east?
DrJ
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Get your battery load tested. I once had a weak battery that would still start the car. Occasionally it would throw a slew of CCM codes after cranking. I assume because the battery voltage is dropped fairly low when I was cranking. This was also an intermittant thing. Replaced the battery and have never seen a CCM code since.
