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

Tiny
VOLFAN2009
  • MEMBER
  • 2005 DODGE RAM
  • V8
  • 2WD
  • AUTOMATIC
  • 43,000 MILES
A "no bus" signal came up in the odometer area of the instrument cluster. Now I have no keyless entry, radio or dome lights. What would this be telling me.
Monday, August 10th, 2009 AT 2:46 PM

80 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
Basically that is telling you there is a break down of communication between the computer and its components. In this case, it may have to do with the body control module (BCM). You need this video to check it.

https://youtu.be/InIlnsjOVFA

Please run down this guide and report back.
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Friday, August 17th, 2018 AT 1:40 PM
Tiny
HAMBONEBROWN
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I had this problem got a used cluster to fix it
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Saturday, October 3rd, 2020 AT 1:36 PM
Tiny
JDSLONE
  • MEMBER
  • 2 POSTS
  • 2004 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 80,000 MILES
I have a no bus message where the mileage should be. All the dash hands arn't working and all the warning lights are on. Truck still runs great but the brake lights and turn signals arn't working and the radio controls on the steering wheel arn't working. I have a hand held scanner but it dosnt' link up with the no bus message on.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
The fact that the dash is not working and you have no communication is telling me the dash cluster is out because it is part of the CAN. You will need to have a used or new unit programmed tot he car here is a video of the job being done on a similar car.

https://youtu.be/_HEC44xENxw

Let me know what you find.

Joe
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
JDSLONE
  • MEMBER
  • 2 POSTS
Great call, I took the car to the dealer and they to do just that cost me $430.00 but at least it works.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
  • 2002 DODGE RAM
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 122,000 MILES
Truck starts and runs. Have no gauges, no headlight control (headlights and taillights are on as well as idiot lights) no control for cruise, radio control (in steering wheel) overhead console not working, no overdrive control, no ac, wipers, fog lights. ABS. What does work is power windows, door locks and yes even with remote (after market) radio, interior lights, door ajar chime, key in chime. Have tried everything that I know battery disconnect, joining positive and negative cables together, checked self test on instrument cluster and it passed, all fuses checked and passed.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Hi,

No BUS means the communication network that the vehicle uses is not operating and the modules that need to communicate are not able to. More than likely this is a failed module or a wiring issue.

Attached you will find the preliminary test that needs to happen to determine the best direction.

Basically, you are going to see if you can communicate with the PCM and cluster. If you can then you probably have a wiring issue. However, you should have some codes in the system even though you disconnected the battery and did a capacitive discharge.

Unfortunately, this issue is not one that a reset will correct. There is a hard fault that needs to be identified and repaired.

Let me know if you have questions. Thanks

Here are some links to similar issues from others:

https://www.2carpros.com/questions/dodge-ram-1999-dodge-ram-quotno-busquot-amp-no-start

https://www.2carpros.com/questions/dodge-ram-2004-dodge-ram-no-bus

https://www.2carpros.com/questions/1999-dodge-ram-no-bus
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Thanks KASEKENNY1. I have many more questions but for now I guess what I need to know is where the modules that I need to test are. I guess I am going to need a wiring diagram and wire color codes? I am asking as I live on a disability income that does not give me a lot of extra income so I have to plan for any major purchases. If you could help you will have my eternal gratitude.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
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Here is the wiring diagram for the PCI and SCI bus for the PCM. However, just checking for voltage is not going to tell you anything other than the modules have the voltage. What you need is the scan tool to plug into the vehicle and see if you can actually communicate with the modules because this is where the fault is. They are saying they can't communicate so you need to see which module cannot and then start testing. Just testing voltage on this type of BUS is not going to result in much more than frustration. Sorry to not have better information.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Okay, this is a update. Showing code p1698. Have removed and cleaned all connections on fuse block and still showing No bu5. Have removed dash and will check for bad connection. Needed to take break. Will update soon.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. Thanks for the update. Keep us posted on what you find. Thanks
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Okay. Checked and cleaned dash connections and still showing no bu5. Guess I will check wiring harness now.
Just wondering if I run a jumper wire from scanner plug to dash on computer (violet) wire if it will give me my dash gauges back? Also I have to walk to service station as I think truck is out of fuel. LOL cause it sputtered and shut off now all I get is it turning over. I guess It pays to keep fuel tank full.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
PWBCKTFTII
  • MEMBER
  • 2 POSTS
  • 2002 DODGE RAM
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Howdy, , I have a similar issue as others I have read here with a twist. When starting the truck when cold I get the no BUS message in the instrument cluster. I understand it mean there's no comm in the CAN BUS. Now here's my twist, if I drive five miles to my local gas station and put gas in the truck and restart it my gauges will work. Though I have the ABS and brake light still on. Different issue I believe. The truck doesn't stall or run poorly. I swapped out what I thought was the PCM and it didn't change anything. The module I changed was the one on the passenger fender with one large connector on it. Is this the PCM? Or is it the TCM? I have and other Module at the same height as the one described but it's on the passenger firewall with three wire connectors on it. What is this module? I replaced the VSS in the rear end and still have the ABS and brake lights on in the dash. It has been suggested I replace the ABS control module, but I want to get the no bus error fixed first. It was also suggested I may have a ground issue. I cleaned the negative cable connections and replaced the braided engine ground with no effect. All connections inspected so far have been clean and tight. Ram 1500 SLT Quad cab if it makes a difference.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,833 POSTS
We had this problem in the shop a while back and we had to get a rebuilt cluster for it to fix it. here is a video of the job being done in a similar car which diagrams below to show you how on your car:

https://youtu.be/_HEC44xENxw

Check out the diagrams (below). Please let us know what happens.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
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I doubt that will get the gauges back because that is just the communication wire from the DLC to the module. More than likely you have an issue on one of the harnesses or a connector is not seated or has water intrusion. As you are inspecting the harness, just disconnect the connectors and see if there are signs of water or any green or discolorations in it.

Sorry to hear about the fuel issue. I have been there and it is not fun.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
PWBCKTFTII
  • MEMBER
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I'll put the instrument cluster on my list of parts to get. I still don't know which control module is which. I also still can't reconcile the warm up issue. Engine heat shouldn't reach the gauges. It may reach the modules or wiring.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Update. I think I may have found the problem in the CTM. I was reading the service manual that I downloaded and found a page that describes what is going on in my truck to a T. Just do not know how to add it here.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,833 POSTS
The control module is interrogated into the cluster. That is what is going out in most cases.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
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Okay. Great. The central timer module is a possibility. Let us know if that takes care of it as that information will help others. Thanks
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)
Tiny
ALTASNOWMAN
  • MEMBER
  • 39 POSTS
Okay, I noticed that the third brake light is working, as are the reverse lights. The turn signal lights work on dash but not on the front or back lights.
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Saturday, October 3rd, 2020 AT 1:37 PM (Merged)

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