No Bus Error

I have seen the cluster go bad and cause this problem here are diagrams and a video of the job being done on a similar car so you can change it out with a used/rebuilt unit.

https://youtu.be/_HEC44xENxw


Check out the diagrams (Below). Please let us know what you find.

Thanks for quick response. I used to be able to stand in the engine compartment and work on engines back when... I have no scanner to check with or what that involves.

Aaah good old days
know you can not fit a small hand in
scanner may and may not help your situation I would be looking at wiring and making sure the PCM have all power and ground needed disconnect PCM and inspect the wiring connector and plugs

My next idea was to pull the instrument cluster and clean up any contacts, as well as getting a hold of a light tester and checking my fuses. When the odometer blinks several times and then the no bus error shows up, an engine icon also lights up, followed in about 10 seconds by a low fuel icon. Should the fuel icon lighting up direct me somewhere?

always check fuses 1st
cluster ???
check harness and power for the PCM

Where I'm seeing a reference to a fuse, that means there is a fuse at that spot? So there could be fuses besides by the battery and inside at the drivers end of the dash?

I've checked all the fuses in those 2 places. I could not get the 2 for the airbags out - had a different type of clip and I didn't want to force them and have the air bags blow up!!

On the diagram, for instance, The Power Distribution Center shows a 20A and a 30A fuse. Is that someplace I should look for fuses also?

And I don't think there's a way I can check the control relays, is there? I have a fuse tester and a circuit tester.

Thanks so much for your help!

Now we have a problem
can not read the wiring schematic
as for the relay just mark it and switch it with similar one
use a test light to check for power at both sides of the fuse
and no need to remove fuse
at the PCM unplug it and check wire where it say power also use a test light and or voltmeter

I can kind of make my way around it, I'm just not an electrician. But I do have a friend that can read those. I'll check back in the morning. And I will check the wiring around the control module. There are 3 major plugs that go into it and I'll check those plugs.

Thanks again.

RICK, I know this thread is really old but I had the same problem and the cluster fixed it FYI

im hving the same issue i just replaced my motor myself it started before the swap but now i have the no bus code help plz

Hello,

There are four fuses (6, 13,11 and 12) that run the BUS we need to check for power. here is a guide to help and the wiring diagrams so you can see how the system works with the fuse locations as well:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Thanks for this thread fixed me right up, I love this site.

Hi guys,
My 2000 Dodge Dakota 4.7L 4x4, Auto trans, reads "no bus" in odometer. I turned it off one night and when I went out the next morning it cranks but won't start and now reads "no bus". Also have no power to the back end of the truck, no lights/signals, and no power at fuel pump. Does this truck have a cut off switch somewhere that has turned off the power? If not where else do I start looking for the problem? Thanks for any help you can give.

Sincerely,
Stuck in the Driveway

"no bus" in the odometer for this situation was a CAM position sensor that went bad. It goes out and disabled several other circuits at the same time. $25 part and plenty of time. It was well worth towing it in and having a qualified shop take a look. Hope this might help someone else...

thnks i have same problem and will try yr advise

i have a 2000 dodge dakota awd 4.7litre
once in a blue moon it decides to just die..... you dont know it dies till you go.....
it wont start until you lrt it cool down for at least 10min......i tried new batt,there is new alt,plugs wires .... when it dies it gave me a code as ... NO BUS ????? if anyone could help give an idea that would be greatly appreciated

thank you all

The no bus means there is a loss of communication between the computer and its components. Check the wiring harness to the PCM and make sure it is tight, and not corroded. Also, check wiring for any damage.

Let me know what you find.

Joe

ok i followed the harness pulled every plug and blew them out .... it all looked good to me... then i found the computer by the air filter ... i pulled the 3 plugs off one at a time ...the one has oil in it???? i think that may be the problem??? its like gear oil is it supppose to be in there??? abd how on earth would it get in there?? its a computer with wires??? im so confused now


thanks for yor help
jason

It is most likely a grease to help maintain electrical connection. Has there been any change?

ok well i went threw all wiring... it does not die all the time ...just once in awhile ...it starts runs fine just once in awhile it will turn off,no warning or nuttin just dead... when it dies i turn the key off and try to start it... it will turn over and over but no fire....if i leave it for bout 10min and let it cool down it will start and i can go again.... i was told maybe it could be my clusters in dash??? im no mechanic and after this truck never be one lol....
i greatly appriciate your help and thoughts

but i went 3 weeks without it dying .. went on a 5 hour trip and it ran fine ... im lost

There is a good chance that when you were moving wires and disconnecting and reconnecting them, you fixed a bad connection. If it starts up again, let me know. We'll figure it out one way or another.

Joe

I have a 99 Dodge Dakota R\T that we had just replaced the transmission in after sitting for about a year and a half in the garage. We started the truck to get the transmission fluid up to temp to top it off, it ran for about 20 minutes at idle when the truck just stopped. Upon trying to restart the engine would turn but not start. The odometer blinks 4 times then shows a No buS message. I tried the key on,off,on,off,on and got a 920 and 921 error. Oh and after the No buS message the check engine light comes on followed by the ABS and gas light, then the security light comes on. I don't know why it just stopped while it was idling. Am I gonna have to get a new computer? Any help would be great. Thanks

The no bus signal identifies there is a break down between the computer and the components. Check to make sure while working on it you didn't loosten any of the wiring going to the PCM. If all is good, you will need to have the PCM tested.

good day joe.... i thought i fixed it too... i let it run for bout half an hour in the drive way yesterday,then it just shut off....bit it restarted right away...i didnt even turn key off.... so now i think maybe fuel pump over heating ???? something is getting to hot and shutting it down??? i have 6 relays that are smokin hot while the others are cold ??

i really appriciate your help


thanks jason

the PCM, or engine computer is like any device that provides power fused. There are two places where all these must be checked with a test light. under the hood and in the interior fuse block also. you know where the engine compartment fuses are, near the battery in the power dristribution center. check em with the key on. the crank sensor gets a power feed from the PCM so if a wire was pinched and as it ran wore through you may have lost any one of 3 or 4 fuses it needs. And the crankshaft sensor itself is a tought nut to get to and easy to get damaged or if it's gray wire gets shorted you may have blew the PCM, the controlling computer for spark, timing, and fuel. Check the fuses and make sure the gray wire has voltage while cranking. ok, I just wanna help. You may have squeexed a wire. Happens all the time, it's not an easy job to change the trans on a truck. Good luck. ok

Which relays are hot?

ok its the 6 on the left of relay box ...
auto shut down
a/c clutch
trailer relay
fuel pump relay
headlamp relay
trans relay

then there are 2 missing under them
thet are suppose to be o2 sensors front and rear

Try replacing the fuel pump relay to see if that takes care of the problem.

Just had three freeze plugs replaced on right side of engine (below manifold). When we got it back, card drove home, but wouldn't shut off. ran for 15 minutes before stopping on its own. Now it will crank, but not start. odometer flashes 4 times then shows "No Bus". Checked connections I could see, all seem ok. Unplugged negative terminal, removed all three connectors from PCM, to no avail. Help?

The no bus indicates there is no communication between the computer and its accessories. Recheck the PCM plugs for damaged pins, corrosion, and make sure it is tight.

Also, are you getting either spark or fuel to the engine? Also, what caused it to finally shut off? That sounds like an ignition switch problem.

hey joe... ok i replaced the fuel pump relay ran it for 20min they never got hot... woo hoo.. im going to take it for drive later this evening when traffic dies and see what happens... but so far idling it ran


i will give you up date tom

thanks joe very much i hope we got it

hey joe ... well that is not fixed at all... barely out my drive way and it was dead... 10min cool down... then started again went for half hour dead again..... half hour cool down that time then started again...brought home and wont start now....

everytime its died it has said "no bus" code again

im ready to give up

The no bus is indicating there is no communication between the computer and its components. There has to be a wiring issue between the two. I'm wondering if the fuel pump is bad and drawing too many amps. That could be why the relay is overheating. God, this would be so much easier if I was there to help.

hello joe

so i dropped my fuel tank today to look at pump....
after it was done there was 2 wires unplugged the main power wires..... the othere 2 are bare wires fuel tank is fukk of dirt,and the filter on bottom of pump is dirty as hell...so im oredering one now monday so i think that maybe the problem
after i get back in i will let you know how it works or what...


i have appreciated all the help and ideas so far....
jason

That sounds like the problem. Let me know how everything works out for you.

Joe

2000 dodge dakota sport 2.5L. truck will not start and this flashes on the odometer. what does this mean?

NO BUS is computer related i have a computer programmer and when its programming no bus flashes on my cluster my guess is ur computer needs a program

hey joe
is it better just try and figure which wire goes where on here before i get a new one ?? or should i just order a new one??

colors that are unplugged are black and orange the2 in the middle plugged in ar black/green strip and pink/black strip

I just tried to find a wiring schematic and found every wire in the vehicle except the pump. Are the wires that are disconnected the same as the ones on the pump?

well my friend joe...

i got this truck runing last night i went 4 hours to get a pump lol.... anyway so far so good ..ran it last night ent for half hour drive ...this am i went fir a hour drive,washed it and it still running woo hoo

i got little more power too of the line,i like that
its idling better and the relays are cool ...

As i said before i really appriciated the help the answers and ideas,i sure hope we got it....
as i get out of my finacial situation here i will send you some money for all your time and thoughts...
i will stay in touch if i have any more trouble but i think we got it


thanks again joe and ttyl

jason