Ok If you can please help me out here...
My son went to the store and when leaving the store the car would not Crank. You turn the key and no starter. Battery is good. All lights work.Radio and widows work. It is also not throwing any codes. When you try and start it the lights on the dash come on but the engine light stays on along with the abs and red security light on solid. Also has a message No Buss.

I'm lost on this one.

 

"No Bus" refers to the "data bus", which is how the various computers in the car communicate with each other and with things that they control. Think of it as a telephone wire that runs between all the fancy electronics in the car. The computers send messages down the wire. Everybody on the wire can "hear" the messages but only those who are interested pay any attention. If that system stops working, the computers can't communicate. There are lots of computer "modules" in the car that need to talk to each other: engine computer, transmission computer, body computer, air bag module, antilock brakes, etc. Even the radio and heater controls are "on the bus".
You are going to need to get some professional help. Somebody with access and knowledge to operate a DRB III (diagnostic readout box) machine to get in there and find where the problem is.

 

Is it possible to disconnect individual pionts in the system one at a time to isolate the circuit that is having the issue?
Thanks Pat

 

Ok here is some information...
I started by trying to figure out which securit was causing the no buss issue and after removing the #8 20 amp fuse the No bus message went away.

The book says this fuse is for the Start/Fuel. Is it possible the fuel modual is not communicating in turn causing the no bus signal disabling the system.
Thanks again.

More in The car did start and run yesterday for a few minutes then stalled and the no bus returned and has not started again.

Thanks Pat

 

Fuses are to protect circuits from shorts in the electrcal power distribution. The data bus is a very low-power system that distributes signals and data. Pulling fuses at home won't restore your telephone service. You need to get a pro in there who knows what he is doing.

 

What I really need is for someone with some real experience with this particular issue to chime in here. I understand your trying to help and I thank you for your input.

With that said I plan to drop the tank in the morning and disconnect the fuel pump module at the tank. I am going to see if the isolation of just that fuel pump module with the #8 fuse in place eliminates the no bus and allows the starter to function.

My current understanding of a data bus tells me if you remove a malfunctioning module from the system it will ignore it and let the rest of the system run.

Thanks again Pat

 

Well today I confirmed proper operation of the Starter and Fuel pump...Jumped the relays. Neutral safety is good also.
Starting to lean towards the CPM..
Later I plan to test the key switch...At this point it's a process of elimantion.

 

Sorry PCM

 

So today I ran through some other tests an then moved to the BCM "Body Control Module" So I dropped the steering column lower cover and after poking around for just a few I uncovered something of interest. O_o
Shortly after the discovery the 747's started showing up and lift me away so it will be Tuesday after work before I get a chance to see if this is the cause of my sons woe's.

 

Also just confirmed BCM is working.