JTEC or NGC Ignition System

[Turbo1Ton]

How can you tell whether you have the JTEC or NGC ignition systems? In the wiring schematics it lists both but I can't really tell how to figure out which one I have.



Thanks,



Jeff

 

[Bob4x4]

JeepTruckEngineController Trucks and Jeeps

NextGenerationController

 

[Wayne M.]

Are you asking about your CTD? or working on a gasser? Are you sure you're looking at the diesel schematic? The above is correct, but refer to gas engine management. I believe the changeover in controllers depends on engine, and sometime during 2002-2005.

 

[Turbo1Ton]

Wayne, I'm asking about my truck. '03 CTD. I'm not sure I'm looking at the diesel schematic. It doesn't appear that they are broken up like that, it seems that they are smashed together depending upon what part of the electrical system you are working on.



Well after further review of the service manual it would appear that I have neither one of them. I sure can't find them under my hood and I've looked everywhere they say it is located. Do the manual transmission trucks not use these?



Jeff

 

[Bob4x4]

The 03 has a pcm on the firewall (passenger side) and the ecm bolted to the engine block on the drivers side(low)



Bob

 

[Wayne M.]

Wayne, I'm asking about my truck. '03 CTD. I'm not sure I'm looking at the diesel schematic. It doesn't appear that they are broken up like that, it seems that they are smashed together depending upon what part of the electrical system you are working on.



Well after further review of the service manual it would appear that I have neither one of them. I sure can't find them under my hood and I've looked everywhere they say it is located. Do the manual transmission trucks not use these?



Jeff

I had to do some thinking back to when I had my '92, and here's what I'm pretty sure the deal is. First, you need the diesel schematic and I don't have a book for my '04 yet. One thing that's been constant since the 12V engines is that Chrysler uses a version of the regular PCM to control things like the trans (O/D, lock up, etc), cruise control and intake heater grid. When the 24V engine came and the engine itself became compuerized, the Cummins and the Chrysler computers were linked to work together. I don't think the '03 Cummins truck uses the JTEC PCM, however I think the old 5. 9 magnum was available as a carryover until the hemi was ready, and I would imagine that truck could have JTEC. Generally, I think that PCM went away with the second gen truck.

You need to look for things like intake grid solenoids and other telltale diesel items in the schematic

 

[rbattelle]

The service manuals I have clearly distinguish NGC, JTEC, and diesel wiring schematics.

JTEC and NGC are both gasser electrical systems.

Ryan

 

[Wayne M.]

The service manuals I have clearly distinguish NGC, JTEC, and diesel wiring schematics.



JTEC and NGC are both gasser electrical systems.



Ryan

I have a 1998 FSM that obvoiusly was printed before the 24V engine, and it shows a JTEC module as a controller in the Diesel diagram. JTEC and NGC are not complete systems, but module foundations. The NGC is supposedly has a much stonger processor group, but the schematic will look similar.



Jeff, to tell weather you're looking at gas or diesel, look for items unique to each. In other words, the gasser diagram will have O2 sensors and coils, the Diesel will have heater grids, soleniods etc. Usually, if it's a chrysler shematic it'll have good identification.

 

[Turbo1Ton]

Wayne, good idea, I hadn't really looked at the individual items.



Bob, I can tell you I have no PCM on my truck. Only the ECM. If I do have a PCM there it is extremely well camouflaged because I cannot find it.



Thanks,



Jeff

 

[Wayne M.]

I found the '05 schematic here

Home | Dodge Body Builder's Guide

There is a PCM shown, but the diagram isn't noted as gas or diesel, and when that happens, it usually means it's the same.

If I can get under my hood today, I'll have a look. According to the '05 diagram, It's stuffed in near the right side of the firewall, like Bob4X4 said

 

[Bob4x4]

None of the 600/610's will have both pcm and ecm,there are a couple other exceptions as well but it isn't important enough to remember everything



Bob

 

[sag2]

None of the diesels had NGC controllers. The 03 and I believe 04 had a Cummins controller on the engine and a JTEC controller on the passenger side firewall if it had an auto trans. Manual trans trucks did not have PCM's. You can tell a NGC controller because it has 4 square connectors.

 

[TCDiesel]

Look for Diesel ,Some of the spec's have multi listing . 4. 7,5. 9,Diesel,Jtec,NGC. Interior lighting would be the same outside of accessories, Air would be different so look for Diesel.