2004 M1084A1 Check Engine Light Troubleshooting

[DFarnham]

Howdy! I have a 2004 Stewart & Stevenson M1084A1 cargo/crane truck that just started displaying a 'check engine' alert on the annunciator panel. All engine instruments appear normal. The truck has been sitting for the last few months (WA winter). Does anyone know which tech manual / section would apply to trouble-shooting this CEL issue? I don't believe it has a OBD-II port to scan codes, and not a lot of FMTV-experienced mechanics up here (remote NW of WA). Any thoughts or suggestions MUCH appreciated.

 

[GeneralDisorder]

It has a standard J1939 port next to the remote battery disconnect switch on the driver's left kick panel. Any heavy duty truck adapter that speaks J1939 can be used with CAT Electronic Technician software to interface with the engine and pull codes, etc.

 

[Keith Knight]

Or take it to a cat service center.
when I had those it turned out to be a sensor and then I would purchase it while I was there and put it on at home. They can also check everything else potentially going on and ask them to save your data in case you ECM goes bad.

 

[GeneralDisorder]

Yes if you can find a CAT dealer that will touch it. Some will and some won't. None of the ones in my area would return calls or didn't want to touch it because it's in an Army truck. Any heavy duty diesel shop should be able to scan it or you can buy a scan adapter and get the software and do it yourself.

I highly recommend acquiring a spare ECM and getting it setup in case you have a failure. The CAT dealer will not do this but there are folks such as myself that offer this service including HP/TQ increase to factory maximum, enabling cruise control, etc.

 

[Mavcaster]

Just went through this myself and solved the problem thanks to the help of @GeneralDisorder and @fuzzytoaster for the hardware and software needed to troubleshoot.

Mine turned out to be the cheapest component in the heui system thank God, injection actuation pressure sensor.

 

[Mavcaster]

Where are you in Washington? I will be out in the Tukwila area week after next and can bring my diagnostic kit and toughbook if not too far.

 

[DFarnham]

Where are you in Washington? I will be out in the Tukwila area week after next and can bring my diagnostic kit and toughbook if not too far.

That is a very generous offer, but I'm off the beaten path a bit, about two hours to the NE in Marblemount, WA. I'd drive the truck down to meet you in Tukwila, but I'm hesitant to drive it that far, out of an abundance of caution, until I figure out what's going on to trigger the CEL. Thanks for even considering it!