CM2350 Active 1894 Code

[Rawze]

The j1939 network (under dash), and network#2 (engine wiring harness feeding vgt, egr, after-treatment components), are each supposed to have 60-ohms resistance on them. This is after the truck is switched off for at least a few minutes.

(Engine harness/ network #2) ...
The 60-ohms comes form a terminating resistor at each end of the network. They measure on their own, 120-ohms each.

Both the (120-ohm) resistors combined, when plugged in properly, makes for the 60-ohms.

== At the one end, the terminating resistor is located inside the VGT turbo controller.

== At the other end, the terminating resistor is down under the truck at either the DEF tank, or at the After-treatment components somewhere.

> BOTH ENDS of the network need a proper (120-ohm) terminating resistor for the network to function properly and have 60-ohms on it. If it is open ended (one or more terminators missing) then the whole thing is susceptible to any nearby electrical noise, and this can damage the components, especially the turbo controller.

Any noise sources like a noisy alternator, noisy inverter or APU, illegal/hi-powered CB radio nearby (or in the truck), someone passing by a radio station, passing nearby power sub-stations, etc.etc.etc. .. can damage (usually the turbo controller) + create ghost faults if the terminating resistors are not installed properly.

> The issue is that there are so many morons out there doing 'deletes' who do bad things to these trucks. Too many people are beyond clueless, and create problems like these. It is not uncommon for some complete dumbarsse to unplug all the after-treatment wiring, etc. and cause one of the terminating resistors to also get unplugged. Then later on, .. eventually, ... someone having a lot of ghost problems, or a fried turbo controller.


(60 ohms) ...
So... with the turbo controller unplugged, you should be getting 120-ohms on the J1939 network#2 engine harness, and with the turbo controller plugged in, you should be getting 60-ohms.

If the end under the truck is unplugged,.. and only the one in the turbo controller remains.. then it will usually be 120-ohms with the tubo plugged in and some random value with it unplugged.

In your case however, you posted that it was shorted out at the unplugged connection that some complete moron did .. so the resistance was lower?. - Hopefully you got this resolved.

The proper thing to do was to LEAVE ALL THE STUFF UNDER THE TRUCK IN PLACE, and hollow out all 3 elements properly (DOC, DPF, and SCR, all 3) to the bare outer shell metal internally, if someone is de-mandating it, but leave all the electrical plugged in.

If all the electrics are missing now, the solution is to ensure that a terminating resistor is installed at the plug under the truck where some idiot likely unplugged everything. Then to seal it all up properly against salt, weather, corrosion, etc.etc.. and this does not mean wrapping it up in electrical tape ... but silicone sealing it properly etc.. or simply to to plug it all back into the electrical components, if they are still in place.

> Get it back to 60-ohms with the turbo controller plugged in.. and it should read 120-ohms with turbo unplugged.

============
(de-mandate programming) ...

NEXT: yes,... you need to also ASAP!!!... copy that program from the ecm and e-mail it to me for a review of what someone did inside that ecm. More than 90% of all de-mandate programming is absolutely harmful to the engine, shortening its life by half or less. - it is nothing to ever take for granted, or make an assumption on. It is as important as preventing sand in your oil... and is just as dangerous, and it has noting to do whatsoever with anyone adding any power to the engine.

info for copy the program: http://rawze.com/forums/showthread.php?t...5#pid72945