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I have gotten this a couple of times, unplug the main connector inside and reconnect it clears up. All grounds look good. What can I check? --- I am here: http://tapatalk.com/map.php?5zlayk 2003 Ram with gauges and a Smarty! Not much more. Sent from my iPhone using Tapatalk

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  • Owner

Here is the reasons for No Bus...

[h=2]Bus Failure[/h] The CCD data bus can be monitored using the DRBIII scan tool. However, it is possible for the data bus to pass all tests since the voltage parameters will be in “range“ and false signals are being sent. There are essentially 12 “hard failures“ that can occur with the CCD data bus:

[*] Bus Shorted to Battery

[*] Bus Shorted to 5 Volts

[*] Bus Shorted to Ground

[*] Bus (+) Shorted to Bus (–)

[*] Bus (–) and Bus (+) Open

[*] Bus (+) Open

[*] Bus (–) Open

[*] No Bus Bias

[*] Bus Bias Level Too High

[*] Bus Bias Level Too Low

[*] No Bus Termination

[*] Not Receiving Bus Messages Correctly

I only recall reading about this on the 06+ trucks with TIPM issues, since you don't fit either of those bills I would start with the work you did and what Michael posted. It may not hurt to buy some dielectric and reconnect what you separated.

  • Owner

The Bus is simply just two wires... Take notice of the 2 twisted wires that is the CCD Network bus.

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[*] Bus Shorted to Battery - Did either wire short to +12 volts?

[*] Bus Shorted to 5 Volts - Did either wire short to a sensor wire +5 volts?

[*] Bus Shorted to Ground - Did either wire short to ground?

[*] Bus (+) Shorted to Bus (–) - Are the 2 wires shorted together?

[*] Bus (–) and Bus (+) Open - Are the 2 wire broken loose somewhere?

[*] Bus (+) Open - Is the Bus + lead broken loose?

[*] Bus (–) Open - Is the Bus - lead broken loose?

[*] No Bus Bias - Is the proper voltage present on the Bus wires? (2.51 Volts and 2.49 Volts)

[*] Bus Bias Level Too High - Is the voltage too high?

[*] Bus Bias Level Too Low - Is the voltage too low?

[*] No Bus Termination

[*] Not Receiving Bus Messages Correctly

What CCD Network does is just like the ethernet cable on your computer for internet. One wire has all the positive pulses and the other wire has all the negative pulses. When the computer see the 2 matching pulse going positive and negative it good information. But when the mirror pulse disappears, or got a spike, etc then the data is bad or corrupt. So after so many tries the computer(s) give up and throw the NO BUS message.