No Bus no communication

Tiny
NICOLEGARZA8898
  • MEMBER
  • 2007 CHRYSLER 300
  • 5.7L
  • V8
  • 4WD
  • MANUAL
  • 200,000 MILES
My car listed above 300c hemi. The engine starts up but doesn't shift gears correctly and my tail lights and interior lights don't work and keeps reading " no bus"" what is it? None of the electrical stuff works.
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Sunday, September 5th, 2021 AT 8:29 AM

5 Replies

Tiny
KASEKENNY
  • EXPERT
The term no bus means your communication network is down. You have what is called a CAN bus network were the different modules communicate with each other via this network.

Here is a guide that will help with this:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

In order to figure out what is going on we are going to need to scan for codes and find out what codes are there so that we can take the next steps.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

More than likely we have an issue with the PCM or cluster but there are many modules on this system so we need to start with codes.

Also, if you want to go ahead and get the bus voltages, you can check this at the DLC. Pin 6 to ground and then 14 to ground. This should be 2.3volts and 2.7 volts which will add to 5.

https://www.2carpros.com/articles/how-to-check-wiring

I suspect you will have something that does not add to 5 volts.

Please let us know what you find and we can go from there. Thanks
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Sunday, September 5th, 2021 AT 4:48 PM
Tiny
NICOLEGARZA8898
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You are wrong that is not what it is.
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Tuesday, September 7th, 2021 AT 7:38 AM
Tiny
KASEKENNY
  • EXPERT
Okay. Can you share how that is the case?

I am actually an engineer with Chrysler in my full time job so I am pretty familiar with this system. No bus means the "bus" communication network has an issue.

The fact that most of your interior functions are not working makes me think we have a module on the interior bus that is preventing the shifting of gears and lighting issue.

However, I would be interested in hearing what you suspect it is as you are looking at it and not me so all I have to go on is what you provide. Please let me know what I am missing. Thanks
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Tuesday, September 7th, 2021 AT 8:01 AM
Tiny
NICOLEGARZA8898
  • MEMBER
The car starts up it won't read no codes and has no communication.
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Tuesday, September 7th, 2021 AT 10:00 AM
Tiny
KASEKENNY
  • EXPERT
Okay. So we have an issue with the communication network as I stated. Which means we need to measure the voltage that I specified above from the DLC so that can see if the network is shorted preventing you from reading the codes. If the voltage is correct then we have a module issue. However step one is checking voltage of the network so that we can find out what is going on. Depending on what they are we can tell what the potential issue is and what steps to take next.

The scan tool communicates with the modules via this communication network. Think of it like a highway. In order for things to travel from city to city (modules are the city) you need a highway for the cars to travel back and forth. If the highway is closed then things can’t get back and forth.
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Tuesday, September 7th, 2021 AT 10:42 AM

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