2002 DT466 code 525

marvelouzone

New member
Hello all. I have a 2002 international 4300 DT466. Just purchased a few weeks ago, when purchased I suspected a few bad injectors, had 357,XXX on dash, had a miss, hard start w/knock when cold... Had injectors tested 5 out of six where bad.. So i replaced injectors with rebuilt/reman ones. Changed oil, oil filter, and fuel filter

After bleeding fuel system, truck started right up cold, but I noticed it still had a miss, upon trying to drive it, it lacked a lot of power very bad. At this point I didn't have a scanner to scan for codes.. truck continued to start for days, just no power, ordered scanner(nexiq) used servicemaxx to get codes, got dtc 525.. upon reading I noticed that rarely is the idm itself the issue, but normally a wiring/clean power issue.. I checked all the known issues, and noticed that all connectors and fuse holders had been changed or removed all together.. I did find bad battery in the process, and replaced. I have not been able to locate ecm relay. Is it in the fuse box? cec relay?

With KOEO standard test passes, injector test brings up dtc525, if I run that same test with injector harness unplugged at valve cover I get 513 and 514 as expected, but no 525. So my question is should I be looking at injector side of harness for problem, or is it still probably a power issue? When truck was starting I was able to verify that all 6 injectors were firing.. just wondering what I really should focus on? is it possible that IDM was really dying causing my misfire in the first place, and now its really dead and does need to be replaced?

my idm is integrated with em, if it is bad do they sell bottom boards for these models as well?
 

Truck Shop

Well-known member
I'm not that experienced with the later dt466E. Longhood is the one on this forum that knows them best. Maybe he can help you.

Truck Shop
 

Longhood

Well-known member
I have been trying to find a link to a troubleshooting guide, that a bus repair company did, maybe try a you tube search if you haven't solved this yet, It has been a while but I think the ECM key on relay is in the fuse box, if the wiring has been messed with you may need to load test the circuits, I just use a seal beam headlight, low is about 5 amps, hi beam is about 10 , and you can use both for a short 15 amp load, many times a circuit will show continuity and voltage, but won't hold a load. the pass through is famous for connection problems, truck lite compound works well.
 
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