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Chris, Shop Foreman
Category: Dodge
Satisfied Customers: 12720
Experience:  Dodge/Cummins and Chrysler Certified Master Tech
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Dodge Dakota Displays No Bus Where Mileage Should Show.

Customer Question

1999 Dodge Dakota RT 'No Bus' showing where mileage is supposed to be. No gauges, no tach, no speed but truck runs good.
I checked for chewed wires, loose grounds, checked TPS, map, crank sensor for proper voltages and all are ok. Truck sat for 9 years due to head gasket problems. Installed new Engine, runs great.
What does 'No Bus' mean?
Submitted: 24 days ago.
Category: Dodge
Expert:  Chris replied 24 days ago.

Hello, my name is ***** ***** I will assist you today.
"No Bus" means that the instrument cluster is not receiving any data from the other computers on the truck like the PCM (engine computer), air bag module, body computer, etc.
Did you have this issue before the truck sat for 9 years?

Customer: replied 24 days ago.
no truck work fine except for over heating when work hard and using antifreeze. no electrical problems
Expert:  Chris replied 24 days ago.
Ok, do you have access to a scan tool that can communicate with the PCM and maybe the BCM or CTM? If not, then can you at least check for any blown fuses?Chris
Customer: replied 24 days ago.
All fuses good.
I have three codes: speed sensor, map sensor, rear oxygen sensor.
None of these affect gauges, tach or other electrical components.
What next?
Expert:  Chris replied 24 days ago.

Ok, the next step is to measure the CCD bus voltage at the data link connector You should have 2.5 volts at terminal 3 and also at terminal 11. Check that and get back to me.

Click on the link below to see the connector.


Customer: replied 19 days ago.
Hello Chris Sorry it took so long to get back to you. i have to make a living too. Your link didn't come through so i had to do a little research to figure out what you were asking me to do. Were you asking me to check on the plug ins below the PCM? and what is a CCD Bus , BCM, CTM. I am a electrician by trade so i know how to back prob a plug to check for voltage. The acronyms are throwing me off. I think you know how to trouble shoot this problem . I just have to under stand what your asking and where these things are. Thanks for your help. Larry
Expert:  Chris replied 19 days ago.

Hi Larry, No I want you to check The CCD bus voltage (Chrysler Collision Detection) at the data link connector under the left side of the dash. I will send the link again. You should have 2.5 volts at terminal 3 and also at terminal 11. Set your DVOM to DC and probe the terminal with the red lead and the black lead to a good ground.

I will send the link again.


Customer: replied 18 days ago.
it took awhile to see it was right in front of me and called it that. i am looking under nth the dash . i call that plug in the diagnostic connector. any way i got no v. on 1&2 , 3 got 4.24, 4&5 0 v, 6 was 4.24,7,8,9,10, n0 voltage, 11 was 4.24, 12 ,13 ,14 ,15,, no voltage, 16 was,12.52 volts , is voltage to high on 3 , and 11 ?
Expert:  Chris replied 18 days ago.
Voltage is too high on 3 and 11. They should each be 2.5 volts. There may be a harness problem or one of the modules on the bus is internally shorted. Lets start by eliminating a module one at a time and see if that takes us anywhere. Disconnect the airbag control module under the center of the dash on the floor. Then recheck 3 and 11. Let me know what the voltage is.Chris
Expert:  Chris replied 9 days ago.

Hello, just checking back to see if you received my last reply. Please let me know if you did or did not. I can always send it again.


Customer: replied 7 days ago.
cant say l have been to happy being handed one step at a time ang then carged for lt
Expert:  Chris replied 7 days ago.
Well, I have not been paid yet, and won't be until you accept the answer. You should have been charged for just the deposit only. In the meantime, have you been able to disconnect some modules and recheck for the proper voltages at the data link connector?Chris
Customer: replied 6 days ago.
I don't Know what a module is or where they are.I do know if I pull the fuses for door locks and the overhead console that keeps track of the miles per gallon, problem goes away.
Expert:  Chris replied 6 days ago.

Aha ! After you said that, I think that you may have a problem with the Central Timer Module (CTM ) or the over head console module. there are 2 possible locations for the CTM . It is behind the left kick panel next to the parking brake , or to the right of the glove box. pull that left kick panel , and if you see a thin module (plastic box with connectors plugged into it), then that is the CTM . Disconnect the connectors going to it and see if the problem goes away. let me know .


Customer: replied 2 days ago.
Hi, Chis Have the right voltage at points 3&11 , 2,7 v when I put fuss in for overhead console I get 4.7v pull fuss back out and put one in for door locks I get 6.4v at the plug. pulled overhead console down found wire chewed on but not shorted to anything. fixing that but I don't think that is the problem. where is door lock mod? CTM is not behind park break on driver side kick panel. passengers side kick panel is stereo amp? 6x8x1 metal box with fins on it. where is CTM?
Expert:  Chris replied 2 days ago.

Ok , sounds like it is the CTM. it is just to the right of the glove box on that year Dakota. Disconnect it there, and then see if the no bus message goes away. Keep me posted .


Customer: replied 2 day ago.
the no bus message is gone as long as I don't put either fuss in for overhead console or door lock.where is door lock module? I have pulled down console and repaird wires there. where you say CTM is, that is stereo amp under passenger kick panel,about 6x8x1 in size, metal box with fins on it?
Customer: replied 2 day ago.
I think we have this problem on the run. Just a little more info. where is door lock module at or is it part of CTM? I think there is a problm around there with bad wires
Customer: replied 2 day ago.
This CTM could be why dome lite, wiper dulay,control circit for blower motor relay, and sterio dont work
Expert:  Chris replied 1 day ago.

The CTM does contain the circuitry for the door locks, dome lights, and wiper delay, but has nothing to do with the stereo or blower motor. However it sounds like you are getting close! And to answer your question about the amplifier, yes it is under the passenger kick panel. I think you are about to solve this!


Customer: replied 18 hours ago.
If the CTM is to the right of the glove box do I have to swing down the dash to get to it? wow, what a chor that is. can I replace it with one out of another truck. It is a year older and it is an SLT with similar package except it is a 3.9, not a 5.9? The Blower motor relay is controlled by the PCM under the hood?. It would be nice to have a little heat now that it is getting cold.
Expert:  Chris replied 11 hours ago.

You do not have to pull the dash. I will send you the procedure. Be right back.


Expert:  Chris replied 11 hours ago.

Click on the link below to see the procedure for removing and installing te CTM.

Let me know if this helps.


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