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"No Bus" what is wrong and how can I fix it?

Tiny
CARUNDELL
  • MECHANIC
  • 602 POSTS
Hey Doug,
Essentially "No Bus" means somewhere communication w/ the various modules (computers) was lost. This could be a controller actually causing this or an intermittent short or open along the bus wiring. Its a very hard problem to diagnose and can be labor intensive, unless the problem occurs when a tech is looking at it!

Chris
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
KOEHLY9372
  • MEMBER
  • 2 POSTS
  • 2000 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 108,000 MILES
I hope you can help me. My truck is getting hot and shutting down. No power, No stering, and No breaks. The reading on the dash reads (NO BUS) wants it cools down it will restart. Please help. Thank You.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
No Bus indicates there is a breakdown of communication between the power control module and its accessories (which are many). Is the vehicle actually overheating or does it just shut down?

Let me know.

Joe
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
KOEHLY9372
  • MEMBER
  • 2 POSTS
The truck is just shutting down when it gets hot. Joe
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
If it isn't overheating but shuts down when it warms up check the wiring harness to the PCM. Make sure it is tight and there is no corrosion. Agani, the no bus indicates there is a break down in communication between the computer and components.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
WHITWHIT
  • MEMBER
  • 1 POST
  • 2000 DODGE RAM
Computer problem
2000 Dodge Ram V8 Two Wheel Drive Automatic 69000. Miles

got my oil changed and tires rotated, next day the NO BUS light came on, ABS light &, gas light, (when I know I have half a tank) and airbag light & gauges dont work on 2000 dodge ram 1500
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
The no bus indicates there isn't a connection between the computer and its components. Check the wiring harness under the hood to make sure it is tight and no one bumped it while they were working.

Also, will the van start and run?

Let me know what you find.

Joe
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,542 POSTS
  • 2000 DODGE RAM
  • 14,900 MILES
In the mileage window it says no bus and when it will start and drive then it quits the gages go all the way down then something clicks and it will start again then shuts down again
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
The no bus indicates there is a break down in communication between the computer and its components
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
TIFFANYJ3571
  • MEMBER
  • 1 POST
  • 1999 DODGE RAM
  • 5.2L
  • V8
  • 2WD
  • AUTOMATIC
I have a 1999 dodge ram 1500 5.2 L/base model/automatic. I went to start my truck one day 3 weeks ago and it would not start/crank, since then I have replaced the pcm module, a variety of different fuses, and I just replaced the crank shaft position sensor and the dang truck still will not start. Do anyone have any knowledge as to what may be the issue? I have already spent a lot of money replacing the things I already mention. I have also tried unplugging all the fuses and testing them with a multi meter. Please at this point I'm begging for help to fix it myself versus taking it to a shop. Also when I try to start the truck the "no bus" comes on after a few minutes when I unplug the battery and re connect it. What am I not checking?
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
The most common cause is a bad ECM. They break down inside and basically can no longer transmit information needed to run the vehicle. Also, they have been known to throw incorrect codes when they fail.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
CHARLES OLDEN
  • MEMBER
  • 2 POSTS
  • 1999 DODGE RAM
  • 5.9L
  • V8
  • 4WD
  • AUTOMATIC
  • 177,000 MILES
I purchased a new ECM plug it up and my vehicle still shows no BUS and all the little ABS brakes and dash lights are on, gauges not working.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello, I'm Danny.

Quick question first. After installation did you you use or have a factory Dodge DRM scan tool used to initiate the module? Otherwise truck with have a code or no start. I've attached a picture below. Hope this helps and thanks for using 2CarPros.
Danny-
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
TOM2OIL
  • MEMBER
  • 2 POSTS
  • 1999 DODGE RAM
  • V8
  • 2WD
  • AUTOMATIC
  • 123,000 MILES
Engine was running fine. Shut it off. Tried to start later. Won't start and have a "no bus" on cluster. Have no spark, fuel pump only works when jumped, ASD relay has been checked OK. Bus+ & bus- both have 2.5vdc.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
The no bus code indicated the computer has lost signal. Check the wiring harness to the PCM to make sure there is no corrosiion and it is tight. If it looks good, have the PCM tested.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
TOM2OIL
  • MEMBER
  • 2 POSTS
Found grounded wire on Crank Position Sensor. Installed new sensor. Truck starts and runs fine.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Excellent job! Glad you found it. Let us know if you have questions in the future.
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Saturday, October 3rd, 2020 AT 1:39 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
  • 2002 DODGE RAM
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 123,000 MILES
I need to know where the different modules are to try to correct a NO BUS issue.
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Wednesday, June 9th, 2021 AT 1:30 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

I attached locations of the PCM, TIPM, TCM and the ABS module for you.

Roy
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Wednesday, June 9th, 2021 AT 1:30 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Thank you. Is there any other modules that I can unplug to try to figure out which is causing me all this grief?
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Wednesday, June 9th, 2021 AT 1:30 PM (Merged)

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