Hi all, just bought a 2001 1500 5.9 4x4. I have researched the many threads out there for no bus coming up on the odometer but the difference between what I am reading and what I am experiencing is that all of my gauges work and the truck starts right up and runs fine. The check engine light comes on at the same time the no bus does.

I have tried the easy stuff, reset pcm, cleaned the ground wires with a wire brush, checked fuses and wires under the dash. I guess I will check the crank sensor next but wanted to get you guys thoughts first.

To throw in a twist it has a remote starter, looks like one of the cheap ones you can get from walmart. Not sure when the no bus problem started as I bought it this way so not sure if that is the problem. Any help is appreciated.

 

Do you have a test light and a multimeter? Find the DLC connector under the front edge of the dash by the steering column. Pin 16 should have 12 volts, pins 4 and 5 Should be chassis and signal ground. Pins 3 and 11 should each have ~2.5 volts to ground. Without this ~2.5 volts, there is no buss. The cluster provides this voltage.


The crankshaft position sensor is not connected to the buss, but all of the electronic modules are. Are there any trouble codes?


Let's do the "key dance" and the actuator tests. Turn the key ON-OFF-0N-OFF-ON and watch the odometer. It will display codes like "P0123" and then "Pdone". Write any codes down.


The actuator test tests all the indicators and gauges in the cluster. Hold the odometer reset down and turn the key on. When the odometer displays "chec", release the button. at the end of the test, there will be a series of numbers in the odometer. Write these down and let us know the results of all your tests.

 

Did the key dance and nothing happens. No code or pdone. Did the actuator test and all of the gauges do their thing and when it's done it goes back to no bus and the check engine light comes on. So I have no codes to share. Got a multimeter and am getting 12v at pin 16. Nothing at 4 and 5 and about 2.5v at 3 and 11 so that checks out okay. I have taken it to auto zone and advance and both have said it won't communicate with their scan tool.

I did find a green and a red wire that are ran up to the DLC but do not connect to anything. They are ran through the smaller hole in the firewall and do not connect to anything under the hood either so not sure what is going on there.

Also forgot to mention that the cruise control doesn't work. The "cruise" comes up under the odometer when you first turn the key on but if I go to set it it does not appear.

 

Begins to sound like a failed central timer module......

 

Is there a way I could test the CTM without replacing it?

 

I don't know.... Maybe dodge dealer could.... Anything in the Service manual talk about it?

 

Ok, so the actuator test of the odometer display (VFD) was ok, all the segments lit up and in the right sequence?


I have never seen all the gauges work with "NO BUS".

 

Think perhaps this is just a cluster issue?

I agree with ya, No Bus usually implies the cluster isn't communicating with the PCM, and I do believe that most of the gauges get their clue from that bus....

 

Here is what it is doing. I have a used cluster coming in the mail, I needed the lens and it was cheaper to buy the whole thing. When it comes in I'll plug it in and see what happens.

 

It has to be internal to the cluster. Something in the control circuitry. There is an operating buss, or the gauges and indicators would not behave normally. They could still pass the test, but not work in normal mode. Wish I had a cluster internal wiring diagram. Can't remember, have you checked it for bad soldering while you have it apart?