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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 4671
Experience:  Owner at DJ Wilson
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Have code 254-8 on 99 dt 466e, start truck idles fine then

Customer Question

have code 254-8 on 99 dt 466e
JA: Thanks. Can you give me any more details about your issue?
Customer: start truck idles fine then hesitates An evenully dies changed wiring harness under vavle cover ,rebuilt injectors ,new harness from vavle cover to senders ,change fuel filter base with remote mount style, new 1 cost 600.00 dollars. new cam sener
JA: OK got it. Last thing — Technicians generally expect a deposit of about $54 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 11 months ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 11 months ago.

Hi my name is***** will be glad to help. Tha fault is for ECM power or loss of communication from your ECM. What model chassis is this?

Customer: replied 11 months ago.
navastar 4900dt sorry had to go on service call
Customer: replied 11 months ago.
Nava star 4900dt
Customer: replied 11 months ago.
Sorry had to go on call out
Expert:  Daniel Wilson replied 11 months ago.

Hi, Thanks for the update. I understand. It is the same for me here actually. We can post back and forth as needed.

Expert:  Daniel Wilson replied 11 months ago.

Start at the battery box and look for corrosion in the harness and connectors and for faulty inline fuses between the battery box and ECM. Check the battery to starter connections including all grounds.

Customer: replied 11 months ago.
Wired around all whether head connection , cleaned all grounds , batteries, starter,cab wirein connection , checked throttle activity change fuel base
Expert:  Daniel Wilson replied 11 months ago.

Thanks for the update... check your relays too including the IDM relay.... they are known for problems and corrosion

Customer: replied 11 months ago.
Changed icp
Expert:  Daniel Wilson replied 11 months ago.

ICP sensor ? Is that 254 fault still active? Check the IDM and IDM relay and harness for problems if so

Customer: replied 11 months ago.
Where is IDM?!
Expert:  Daniel Wilson replied 11 months ago.

Click here for the diagrams.

Schematics

Customer: replied 11 months ago.
Where is IDM?
Customer: replied 11 months ago.
Put ground wire from computer to starter ground no more 254 code but it still stumble at idle randomly?
Expert:  Daniel Wilson replied 11 months ago.

The IDM will be on the firewall engine drivers side. Click here and see PDF page 57 Id try bypassing or changing the IDM relay and confirm power to the IDM or you have a possibly faulty IDM or ECM if the harness and relays check ok and there is good power and ground. See if you can access a test IDM or ECM from a possible salvage yard etc....

Diagrams

Customer: replied 11 months ago.
Would abs sensor bad cause engine to stumble
Customer: replied 11 months ago.
IDM has no power at terminals ,unplugged should it have?
Expert:  Daniel Wilson replied 11 months ago.

There should be power to it with the IGN switch on. If not then go to the IDM relay and check it or try bypassing it

Expert:  Daniel Wilson replied 11 months ago.

Possibly faulty IDM relay or harness problem

Customer: replied 11 months ago.
Which one is IDM relay?
Expert:  Daniel Wilson replied 11 months ago.

The relay should be on the firewall near the IDM. There should be two or 3 there.... The schematics will help identifying the correct one.

Customer: replied 11 months ago.
Ok I'll check ,will check with u Tommorow thanks
Expert:  Daniel Wilson replied 11 months ago.

Pleasure to help

Customer: replied 11 months ago.
My blue point pocket IQ won't read computer saying no ecm detected but truck is still dying
Expert:  Daniel Wilson replied 11 months ago.

It will not read the module if there is no power and ground to the module and is not powered up. Verify your power and grounds first.... If ok and wont read or communicate, try a test module or have bench tested and reflashed to see if it will take a reflash or needs replacement.

Customer: replied 11 months ago.
Ok I will try it
Customer: replied 11 months ago.
Gauges have quit workin & no communication to computer now .still can't find IDM box hav about 12 wires on firewall not hooked up to nothing look at diagram don't understand where IDM at inside cab or outside of cab IDM replaceable ?
Expert:  Daniel Wilson replied 11 months ago.

Check the connections in the battery box. There should be some inline fuses coming off the POS cable for ECM power...... Test power to the engine ECM and verify ground and switched power. If ok and no communication, you have a bad ECM

Customer: replied 11 months ago.
Which pins are supposed to be hot key on /off -page 6 shows pin # ***** I can't find no description for location of pins I have only one pin hot with key off/ several hot with key on . Don't know how their numbered (this is main harness to computer)
Expert:  Daniel Wilson replied 11 months ago.

go to pdf page 55

Customer: replied 11 months ago.
We found 97rh or 97 star h that's hot. Can't tell, hard to read.
Expert:  Daniel Wilson replied 11 months ago.

Ok Ignoring the wire numbers, lets try the PINS on the connector... See the schematic... Bat power leads to pin 25 switched power leads to pin 24........... 21, 22, and 41 are all on the power side of the circuit depending on the ECM relay position whether they are energized.

Grounds lead to 1,2,23, 42

Customer: replied 11 months ago.
Ok thanks talk Tommorow
Expert:  Daniel Wilson replied 11 months ago.

Sounds good.

Customer: replied 11 months ago.
Put a different ecm with same number on it and the gauges work & can communicate to computer , doesn't die now but takes a lot longer to throw 254 8 code
Expert:  Daniel Wilson replied 11 months ago.

Thanks for the update. that means the ECM had problems for sure from low voltage or other reasons but you have an intermittent power issue or grounds to the ECM still.... Possible short, corroded harness/poor connections or ignition power/ charging system issues.

Expert:  Daniel Wilson replied 11 months ago.

Test all your batteries with a digital tester for dead cells etc, clean/inspect/tighten all cable connections and grounds from batteries to starter and chassis grounds. Test the charging system for any problems and for shorts or draws. If ok inspect the engine and ECM harness thoroughly and the connector pins in the harness and through the firewall for corrosion, etc.

Expert:  Daniel Wilson replied 11 months ago.

sounds like you are gaining and it is likely the voltage issue caused the first ECM to fail over time.

Customer: replied 11 months ago.
We have tested the wires that plug into the computer and we have found fluctuating voltage on a couple of the wires, don't know which one they are yet, there is one wire that is hot all the time. When we start the motor, the voltage fluctuates, the clutch safety switch and the guages work intermittingly
Expert:  Daniel Wilson replied 11 months ago.

Investigate further into that problem and circuit.

Customer: replied 11 months ago.
W
Customer: replied 11 months ago.
We replaced two relays and now it doesn't die or stumble but now we have no gauges working.
Expert:  Daniel Wilson replied 11 months ago.

No gauge response at all? No power to the gauges or the gauges cycle with key on but do not work? Which ECM is hooked up? If the test one, Try having it programmed for your truck VIN and see if everything works.

Customer: replied 11 months ago.
Put old ecm back on ( only borrowed the other one ) gauges cycle but afterwards don't work
Expert:  Daniel Wilson replied 11 months ago.

But likely worked with the other ECM..... Have the ECM reflashed and tested by the dealer. Sounds like an ECM problem, harness/datalink or ESC cab controller problem. If they work with the other ECM it would have to be a problem with the ECM.

Customer: replied 11 months ago.
Ok thanks got to go , talk Monday
Expert:  Daniel Wilson replied 11 months ago.

Pleasure to help

Customer: replied 11 months ago.
I am taking the truck to the International house to have the computer flashed. Update you later. Thanks
Expert:  Daniel Wilson replied 11 months ago.

Thanks for the update. Let me know.