bus communication problems

[moTTD]

I've got a '04 3500 4wd 5sp with 180k on the clock. I bought this truck about 6 months ago after many great years with my old D350. I was resistant to going with a 3rd gen as I'm a pretty knowledgeable mechanic, but I'm not a "wires" guy.I love the truck, but sure enough, now it's developed a nasty intermittent electrical problem. Every once and a while, it will suddenly go crazy in the dash board, with all the gauges bouncing, lights flashing, bells and gongs all going off. Fortunately, the engine never (at least not yet) misses a beat, but I found that even the brake lights go on and stay on when this happens. Sometimes the odometer will display "NO BUS" when this happens, and when scanned, I get the codes 336 and 1652. I just replace the crank sensor (336) a month ago, and I know that the 1652 is the bus communication code. I replaced the original batteries, and checked to see if my aftermarket radio was the problem (not!) -- and I removed the ECM plugs, sprayed them, and reattached them -- no joy.....I've looked at the bus diagnostic page in the article section and I really don't understand it, I'd really appreciate any other ideas, pointers, or links that might help me.Tom

[Mopar1973Man]

http://articles.mopar1973man.com/3rd-generation-dodge-cummins/60-obdii-error-codes/365-p1652-j1850-short-to-ground http://articles.mopar1973man.com/3rd-generation-dodge-cummins/60-obdii-error-codes/308-p0336-crankshaft-position-ckp-sensor-signal Here is a start...

[moTTD]

Thanks!OK, I'll get out the old Fluke and have at it.... Is there an online site that I can use to show how to find and identify these circuits?Tom

[Mopar1973Man]

Not yet... But let me dig around and I'll see what I can find.

[moTTD]

I think I found the problem....There were a couple of harnesses kind of wrapped around the dipstick tube. They were several wires rubbed bare and probably shorting there. I'm not sure they are OEM wires, they may be from some of the Banks stuff that came on the truck?Anyway, the dash seems to be behaving itself now -- we'll see....

[AH64ID]

Glad you found the issue.

It's hard to say if that stuff is OEM or not, it's a little different than my 05, but the 04.0's were different. I don't see the Banks needing to adjust any of the signals thru that harness.

My 05.