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Mrkentee · 06-21-2025, **(Subject: J1939 problem )**

Could a rubbed wire on an unused sensor on a demandated truck possibly be causing havoc with the J 1939 network?
Specifically, communication between engine and dash gauges.

Rawze · 06-21-2025, **(Subject: J1939 problem )**

(06-21-2025 )Mrkentee Wrote: Could a rubbed wire on an unused sensor on a demandated truck possibly be causing havoc with the J 1939 network?
Specifically, communication between engine and dash gauges.

The dash and gauges, ABs and other vehicle things all communicate on canbuss #1 network.

The DPF, EGR, turbo, etc.. and other engine specific things communicate on canbuss #2 network. A completely separate network.

if canbuss #1 network is acting up due to something shorting out, etc.. then the inbalance could be seen by using an oscilloscope while its acting up.

Mrkentee · 06-21-2025, **(Subject: J1939 problem )**

(06-21-2025 )Rawze Wrote:
(06-21-2025 )Mrkentee Wrote: Could a rubbed wire on an unused sensor on a demandated truck possibly be causing havoc with the J 1939 network?
Specifically, communication between engine and dash gauges.

The dash and gauges, ABs and other vehicle things all communicate on canbuss #1 network.

The DPF, EGR, turbo, etc.. and other engine specific things communicate on canbuss #2 network. A completely separate network.

if canbuss #1 network is acting up due to something shorting out, etc.. then the inbalance could be seen by using an oscilloscope while its acting up.

Like last time, it’s back to normal after about 2 days. I’m thinking rubbed wires snd moisture. But look at all these counts of ABS controller and 1939. Which causes the other? Is it most likely an ABS problem? I thought it was the other way around.

(My lower radiator clamp broke and I lost all my coolant. That’s what all those are about.)

Mrkentee

It was fine until Thursday, a few hours after my lower radiator hose clamp broke, and dumped all my coolant. On Friday I pulled out from a loaded trailer, snd everything came back. It lasted about 1/2 and hour. The next morning I pulled the terminating resistor out, and it came back again. That lasted until I turned on the wipers and washer fluid. Finally Saturday afternoon it eventually came back to normal.
Today I hit some light rain for a short time, which I didn’t think would matter, and it did it twice for a second or two.
So it seems moisture related. I just spent another 3 hours or so under it, and can’t find anything rubbed, or otherwise. I sprayed water on everything. I’m stumped.