99 Freightliner N14+ code 343 after overheating

Last week I ran to Virginia. Going up hill on I-64 I had a return hose blow out and had a severe loss of fluid. I put 9 gallons of fluid in radiator to fill it again.
The temperature warning light did not come on, only my low coolant alarm. Motor did not shut down.
Since then I have driven 1200 miles with no problems. Today doing typical maintenance. Checking belts and fluids. Tightened belts.
I started truck to check belts. Truck started and ran fine. I shut the truck off and hit the diagnostics switch now the yellow check engine light stays on. It flashes a 343 code.
The grounding fuse was blown between the ECM and the block. I changed the fuse. Cleaned all grounds on chassis, starter, alternator and batteries.
I even disconnected EPS and the ECM cleaned connections and reconnected. I also disconnected alternator while truck was running, no change in warning light.
Truck starts and runs normal but the yellow check engine light stays on and same code when I check it.
Is my ECM going bad. Could it some how overheated or shorted out when my radiator hose blew open. I had coolant all over the engine compartment.
I plan on taking it to a Freighliner dealer tomorrow and have it checked. I think I know the answer just hoping I missed something.
Thanks for any advice.

 

January of 2014 I changed the EPS and the ECM. To clarify the ECM I installed came from a Volvo same year same motor. I haven't had any codes until yesterday. Truck has been running good.
I was reading my old emails and this same phenomenon was active when I first installed this ECM but it stopped. I just didn't remember.
How do I clear codes. I disconnected ECM cleaned those connections and also disconnected batteries, I would've thought that would clear codes. Something else I need to try.
I did put my original ECM back in to see if it would work, apparently the company I paid to repair the old ECM did not do it.
BUT the code did go away. When I put the working ECM back in the code was there again.
Thanks for the tip to clean Injector connections. I will go do that now.

 

Bad news (for me) as I sit in Des Moines Pilot. The red stop engine light came on. I started to get a little nervous. Luck me I got into the truckstop. Hauling an oversize load. My bees got postponed.
When I shut truck off and did the diagnostic check. I get a code 111.
Imminent ECM failure. Well heck that doesn't sound like fun.

4 weeks I ago I needed a tow truck to get me home to change my transmission. This time I can change the ECM here in the TS parking lot.
As long as I disconnect batteries first. I can just unbolt ECM and replace, correct? Nothing to short. I can buy a Rebuilt ECM with a year warranty here in DesMoines.

Hopefully I'm rolling by noon.

 

20 minutes to remove ECM. 1.5 hours to wait for taxi. 10 mile ride to Cummins. 1 hour later. Pocket $3300 lighter. 10 mile ride back to truck. 20 minutes to put back in. On the road By 1pm. Not such a bad delay, time wise only 6 hours.

Cheaper than a tow and waiting for a garage to install an ECM, and who knows how many tests charged to affirm the ECM was bad.

062 I 've had the ECM out of the truck about 10 times in the last year. Those wires are limber. But you're right take it easy with the old harness.