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Discussion Starter #1

Here is a video of my 2008 GMC Duramax. As the video shows I get a number of DIC messages, the instrument cluster goes dead along with the radio. Once it does come back the TPMS icon stays illuminated but going thru the DIC shows each of the tire pressures. The gages come back and the radio starts up again. Then once I shut down the truck the radio will keep running till I open the driver's door is opened. This is normal but after this issue occurs when you open the driver's door the radio will still stay on for 3 to 4 seconds before turning off. The dealer's shop said the issue is most likely the instrument cluster since each of those DIC messages are from the VCM (instrument cluster). The dealer replaced the cluster but a few weeks later the issue reappeared. I did at one time have the issue and was able to put my code reader on it. Can't remember the exact code but it showed a loss of communcation with the VCM. Has anyone ever seen an issue like this before? The only thing that scares me about this when I shut the truck down when the messages are flashing the truck will not crank. I have to let it sit for a few minutes then it starts like nothing was wrong. Dean
 

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At least some of those messages come up because the ABS light is on. Fix the ABS light problem (whatever that might be) and messages about trailer wiring, trailer braking, etc will go away on their own. It would be helpful if you could get that code relating to the VCM.
 

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At least some of those messages come up because the ABS light is on. Fix the ABS light problem (whatever that might be) and messages about trailer wiring, trailer braking, etc will go away on their own. It would be helpful if you could get that code relating to the VCM.
I am carrying my OBS2 code reader for the next time this happens. I have a hard time believing that there are separate issues at play here since all 4 messages come on at the same time along with the ABS and airbag icons. Dean
 

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Usually when you have lots of error messages, things not working correctly, it's a circuit problem or problems. You said that at one time you had a loss of communication with the VCM or Instrument cluster. Sounds like you need to solve the communication problem. A wiring diagram might be useful for your research. You likely can find what you need here
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Sounds like a low speed comm network issue. I assume this thing doesn’t store any codes in any modules after this happens?
 

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Sounds like a low speed comm network issue. I assume this thing doesn’t store any codes in any modules after this happens?
It will show an active fault with the vehicle still running after this happens but nothing in history. Even had the service center check and nothing stored. One thing I did back in 2010 was install a Pioneer touch screen deck with a module adapter so there would be no codes set for loss of communication with the VCM and the ability to use the steering wheel controls. I suppose it is possible that that interface module I got from Crutchfield might be bringing down the databus but I am still surprised that when this happens that it kills the Pioneer deck also. The loss of the databus or a problem with the interface module I think would turn off the stereo deck. It almost seems like the instrument cluster might be losing power from a weak connection or ground. Dean
 

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It will show an active fault with the vehicle still running after this happens but nothing in history. Even had the service center check and nothing stored. One thing I did back in 2010 was install a Pioneer touch screen deck with a module adapter so there would be no codes set for loss of communication with the VCM and the ability to use the steering wheel controls. I suppose it is possible that that interface module I got from Crutchfield might be bringing down the databus but I am still surprised that when this happens that it kills the Pioneer deck also. The loss of the databus or a problem with the interface module I think would turn off the stereo deck. It almost seems like the instrument cluster might be losing power from a weak connection or ground. Dean
Yes! Those modules are VERY well known to take down the LS data bus. So are aftermarket radios. I would disconnect them both and see if your issue goes away. This is one of the biggest reasons why I keep factory radios in both of my vehicles because I like the steering wheel controls and have been burned too many times by those add on modules. Usually the radios won’t screw things up too often but if they try to talk on the LS bus at all they will screw the bus/network up.
 

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Discussion Starter #8
Yes! Those modules are VERY well known to take down the LS data bus. So are aftermarket radios. I would disconnect them both and see if your issue goes away. This is one of the biggest reasons why I keep factory radios in both of my vehicles because I like the steering wheel controls and have been burned too many times by those add on modules. Usually the radios won’t screw things up too often but if they try to talk on the LS bus at all they will screw the bus/network up.
I may have to do that. My problem is the issue is very intermittent. It won't happen for weeks then go off 2 or 3 times in one day. One question I have is would the loss of the LS bus cause the radio go out? The Pioneer deck I put in is a fairly top end unit but the module looked pretty cheap. I may look at putting the stock radio back in but even that involves quite a bit of rewiring. Dean
 
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