Engine/Transmission (1998.5 - 2002) What The? Ding .... Ding .... No BuS

[ToolManTimTaylor]

Hopped in the rig tonite ... ... WHAM! bad idle , Ding Ding , NO ..... NO guages! , Check Engine staring me dead in the face.



"No Bus" was in the window. I shut down and cycled the key and had just about every code known to man :'( (all P-codes which I thought to be odd)



Hit the key again and ... ... fired right up as if nothing ever happened ... ... What gives? It's so freakish that I am left



I allways wait to start as I NEVER start it when the fuel pump is running prime. (that P. E pump lets you know it's running too ) I wait 'til either the light goes out or the Fuel Pressure guage returns to zero so when I do start it the VP44 only gets 12 lbs of fuel.



I am gonna check the codes with my books in the A. M.



Any Ideas? Pcm clips all snug in place.

 

[parcher]

Bus problems stump technicians, nearly impossible , no absolutely impossible to diognose without a drb and a very clear understanding of vehicle communications. Most of your "p" codes are going to be "no bus message from 'X' module" where 'X'= just about everything on the bus. For the uninitiated the bus is basically the phone line that all of the controllers talk to each other over.

 

[Gary - K7GLD]

Most of those communication lines are independent from each other - but ONE thing they ALL pretty much share, is GROUND return! Thoroughly check, clean and tighten all the ground straps you can find around the engine and computers...

 

[Straight6Jeff]

Check the Central timing module. The tech manual has a detailed flow chart of the NO BUS syndrome.

 

[Marco]

No bus

I've seen several times that No bus thing.

It's always been the ECM plug soaked with diesel after a filter change. Cleaning and a little di electric grease has always solved

the situation.



Maybe yours too???

 

[ToolManTimTaylor]

MARCO! Whats happenin' man? I kinda thought back a bit and I replaced the filter back when I did the PE 4200 pump setup 3 months ago so that didn't jive. HOWEVER... ... guess what Mr dummy forgot what he did yesterday ... ..... WASH THE TRUCK (And fender wells) Gee could it beeee Runs great now.

 

[parcher]

Gary KJ6Q, Those bus lines are anything but independent of each other The CCD bus uses a twisted pair of wires and neither one is technically a ground. The lines are identified in the wiring diagrams as bus- and bus+ but this could have just as easily been bus(a) and bus(b).

 

[Bob4x4]

The Bus+ will be at about 2. 6v and the Bus- will be about 2. 4v. Any module on the bus can pull that voltage down and kill that communication. Either side can also be shorted to ground or B+which will also kill comm. Of course we can also see an open on either side.

These issues can be fun to check out but rule of thumb,remember what you worked on last and check that first.



Bob