N14 intermittent skip, ecm active code of 343 and check engine light stays on

Ok so my 97 w900l is having a intermittent skip, truck was running fine last week, I went out to start it last night and it cranked a lot since I forgot to plug it in, but once started it ran fine for about 1.5 hrs then it died. I went out to restart it and it was skipping with the check engine light on. So this morning I took down to the local shop and they hooked it up and read the codes, it is showing a active code of 343 relating to the ecm/ grounds. I have checked the chassis grounds and cleaned them all up by the starter and I found a bunch of corrosion in the battery box.I replaced one cross tie that was rotted off and cleaned everything and sprayed dielectic grease on all of the connections. Anybody have any ideas?
 
Sounds to me like you got it.

With any engine that has electronic controls, the grounds are the very first thing to check when you have a problem. And the things you mentioned, corrosion, "rotted off cross tie", etc. are all things that will cause the problems and code you mention.

Plus you have an old truck. Although you don't mention the mileage, any rig that old is going to present things like this, especially when they are neglected. And your description of the corrosion and stuff indicate to me what I looked at for 30 years of working on trucks. All too often drivers don't think about this stuff until the check engine light comes on.

And speaking of the check engine light, a few cycles of key on key off should clear the code once you have cleaned up all the grounds. Oh, and while you are at it, take care of the positive cables too.
 
I would replace all battery jumper cables. replace both hot & gorund main cables. corrosion gets under the coating where you cannot see it.
 
* Loose engine or chassis ground connections can cause Fault Code 343 to be logged, as well as complaints of an intermittent stumble. Pay special attention to the negative starter post connection.
* Moisture in the ECM connectors can also cause the ECM to log Fault Code 343. Refer to Service Parts Topic 95T19-12A for details on water intrusion.
* A damaged EPS can cause the ECM to log Fault Code 343 and possibly Fault Code 121 and Fault Code 115.
* Defective alternators occasionally cause FC 343. Run the engine with the alternator belt off; if the fault code becomes inactive, replace the alternator.
* Intermittent battery shorts to ground may cause the fault.
* Intermittent shorts to ground in these circuits: injector solenoids, injector harnesses, fan clutch solenoids, fan clutch wiring, engine brake solenoids, engine brake wiring, OEM installed engine speed sensors, flywheel housing and associated wiring, datalink wiring, and fuel shutoff solenoid or wiring may cause intermittent Fault Code 343.
* To determine if conducted electrical noise through the grounds is causing the Fault Code 343, unbolt the ECM, and move it away from the engine block so that it is isolated from the engine block ground. If the fault is not duplicated, troubleshoot for the source of the electrical noise.

found this on a cummins site
 
* Loose engine or chassis ground connections can cause Fault Code 343 to be logged, as well as complaints of an intermittent stumble. Pay special attention to the negative starter post connection.
* Moisture in the ECM connectors can also cause the ECM to log Fault Code 343. Refer to Service Parts Topic 95T19-12A for details on water intrusion.
* A damaged EPS can cause the ECM to log Fault Code 343 and possibly Fault Code 121 and Fault Code 115.
* Defective alternators occasionally cause FC 343. Run the engine with the alternator belt off; if the fault code becomes inactive, replace the alternator.
* Intermittent battery shorts to ground may cause the fault.
* Intermittent shorts to ground in these circuits: injector solenoids, injector harnesses, fan clutch solenoids, fan clutch wiring, engine brake solenoids, engine brake wiring, OEM installed engine speed sensors, flywheel housing and associated wiring, datalink wiring, and fuel shutoff solenoid or wiring may cause intermittent Fault Code 343.
* To determine if conducted electrical noise through the grounds is causing the Fault Code 343, unbolt the ECM, and move it away from the engine block so that it is isolated from the engine block ground. If the fault is not duplicated, troubleshoot for the source of the electrical noise.

found this on a cummins site

They'll leave anything laying around, won't they?
 
that was only half of it
they wanted you to lift the tractor up with a tow truck
and drop it a couple of times
see if that would work
 
Thanks for all the replies guys. It has been running good this week so far no skipping but the check engine light wont go out so i;m assuming I have more wires to chase...
 
* Loose engine or chassis ground connections can cause Fault Code 343 to be logged, as well as complaints of an intermittent stumble. Pay special attention to the negative starter post connection.
* Moisture in the ECM connectors can also cause the ECM to log Fault Code 343. Refer to Service Parts Topic 95T19-12A for details on water intrusion.
* A damaged EPS can cause the ECM to log Fault Code 343 and possibly Fault Code 121 and Fault Code 115.
* Defective alternators occasionally cause FC 343. Run the engine with the alternator belt off; if the fault code becomes inactive, replace the alternator.
* Intermittent battery shorts to ground may cause the fault.
* Intermittent shorts to ground in these circuits: injector solenoids, injector harnesses, fan clutch solenoids, fan clutch wiring, engine brake solenoids, engine brake wiring, OEM installed engine speed sensors, flywheel housing and associated wiring, datalink wiring, and fuel shutoff solenoid or wiring may cause intermittent Fault Code 343.
* To determine if conducted electrical noise through the grounds is causing the Fault Code 343, unbolt the ECM, and move it away from the engine block so that it is isolated from the engine block ground. If the fault is not duplicated, troubleshoot for the source of the electrical noise.

found this on a cummins site
What is FC 343?
 

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