Stuck in limp mode

[SkullGirl]

Help
I have a 2000 3800 t444e IH school bus compressor went down which cause bus to go into limp mode. No reving of engine while driving, but wont go past 3rd gear or over 35 miles an hour. Paid a shop $2000 for the work and new compressor but still stuck in limp mode. Anyone know how to get bus out of limp mode?
Stuck in Ceader Rapids Iowa .
No clue where to turn or what to do .
Checked and cleared all codes,rechecked no codes listed other than 111 which is no earor codes .
Can someone please help?

[ewo1]

Please dont double post…

Your air compressor has nothing to do with the transmission , speaking of which, which allison model do you have ?
Do you have a check trans lite “on” in the dash?

Have you checked the fuse for you transmission computer, assuming your is not an at545.

First thing you need to rule out is an electrical issue. Find the fuse!

Also, read this thread -> https://www.skoolie.net/forums/f37/r...ght-44000.html

[SkullGirl]

No check trans light
It is an at545

[SkullGirl]

No check trans light
It is an t545

[nikitis]

If there is no check trans light then maybe the bulb for the light is blown in the gauge cluster. I'd replace it and try again.

If still no light it's weird cause the 545 is all mechanical but the engine should be able to tell something is wrong.

I would suspect an ECU issue but your getting 111 which means all is well. So it could be that it's too dumb to know since the trans is mechanical , or the sensor that detects it is bad and not reporting it. Or it's reporting but gauge cluster bulb for the trans light is burned out and it can't tell you. But it's looking more like the trans bought the farm. 545 isn't a good transmission.your bus is new enough you have some better transmission upgrade options.

[ewo1]

Originally Posted by SkullGirl

Help
I have a 2000 3800 t444e IH school bus compressor went down which cause bus to go into limp mode. No reving of engine while driving, but wont go past 3rd gear or over 35 miles an hour. Paid a shop $2000 for the work and new compressor but still stuck in limp mode. Anyone know how to get bus out of limp mode?
Stuck in Ceader Rapids Iowa .
No clue where to turn or what to do .
Checked and cleared all codes,rechecked no codes listed other than 111 which is no earor codes .
Can someone please help?

How are you pulling codes?
Do you have servicemaxx?
When was the last time you changed the fuel filter?
does the check engine light turn on when it goes limp?

Are you familiar with all the sensor locations on your engine?

Please explain how the compressor threw the bus into limp mode.



If you can drive 35 mph, your not stuck...just moving slow!

[ewo1]

Not knowing how experienced you are with fixing your motor.....

I'll share a short happening...my '99 Dt466 had been sitting for about 3 months without starting or driving and when I went to drive it the check engine light would go on and it would go into limp mode within 2-3 minutes of driving.

I removed the IPR, cleaned it out with brake cleaner and lubed it back up with WD40, no more limp mode !!!

I'm thinking maybe moisture got into the ipr and it started to "stick" causing the CEL and limp mode. Can't say this is your problem but your not providing enough info to help you out.

[ewo1]

A question for those who have been there and done that....EBPV - Exhaust Brake pressure valve.

I am not ashamed to say that I know nothing about the T444e motor...I barely learned enough on the DT466 to keep me off the roadway shoulder....

So this scenario of "Limp mode - no codes" got me curious to learn more...

From what I have read so far, not all T444e will have the Exhaust Brake sensor installed, it is an optional item.

What I did understand so far that the EBPV helps the engine warm up faster but when the valve closes it will make the engine feel like it has no power.

when the valve sticks closed, build up from soot, can cause the valve to stick shut/closed.

My questions would be, if equipped with a EBPV, could this "closed/stuck valve cause a "limp" mode with no DTC showing?

Would there be any "smoke" which might help indicate a stuck valve?

As the EBPV is optional, in motors with NO valve, how is back pressure measured or controlled?

[nikitis]

I have like the first model T444E and I have no clue about the EBPV

[SkullGirl]

Got the codes With flash codes
134 APS signal and IVS disagree

325 Power reduced, matched to cooling system performance

321 Engine Coolant Temperature above warning level

236 ECL switch circuit fault

626 Unexpected reset fault

After clearing codes got the 111

[cadillackid]

Originally Posted by SkullGirl

Got the codes With flash codes
134 APS signal and IVS disagree

325 Power reduced, matched to cooling system performance

321 Engine Coolant Temperature above warning level

236 ECL switch circuit fault

626 Unexpected reset fault

After clearing codes got the 111

3 codes stanbd out to me..


1. your 134 this is a common reason the computer goes into "dead pedal" mode.. by dead pedal meaning it will not go past idle.. you floor it and it just sits.. the pedal assembly has a sensor that tells the computer how far down you have the pedal... it also has a switch that knows when your foot is completely off the pedal... if the foot switch reads that your foot isnt on the pedal but the sensor shows its being pressed, it issues a code and disables the pedal... if the pedal sensor shows 0% throttle yet the foot switch says your foot is on the pedal then it issues a code and disables the throttle.. its often the pedal assembly or sensor / switch on the pedal itself thats going bad.. or its wiring going to the pedal...



2. the 321/325 are "limp mode" codes.. the computer thinks the engine was being severely overheated and thus was reducing power as a way to try and warn the driver something is wrong but also to try and protect itself from damage if in fact it is overheating... so the first thing to check is was the engine overheated.. or showing signs of it... ie low coolant, driving in real hot weather and the fan wasnt working.. was the dash gauge reflecting any over-temp? red oil / water light flashing? thermostat stuck? if the codes come up and the engine is not actually overheating then the coolant temp sensor is often the culprit... it makes the computer think the engine is much hotter than it really is.. im not sure how the code 236 plays into this.. its seeing a engine coolant level circuit fault.. i dont know if that means the engine is low on coolant or if theres a wiring fault...



I would think after the mechanics replaced the compressor theyd have refilled thye coolant and checked for codes.. the compressor wont limp the engine.. however it wouldve started to drag down the bus with the spring brakes and go into alarm if you lost pressure and have air brakes.. and tried to keep driving...



if you drive and it still wont go above 30 even cold.. (remember your engine can actually overheat within minutes of starting if its super low on coolant or the thermostat is stuck).. then read the codes again and see what comes back... I believe you can clear the codes by pulling the ECM BAT, DIAG, and gauges fuses from the dashboard fuse panel for 1-2 minutes,(key off) inserting them back and check to see if theres no more codes.. then drive.. sometimes after pullingthe fuses youll get an abnoral battery coltage or power loss code.. (normal)...



id start with the simole stuff.. check the coolant level.. make sure the belt is on all the pulleys.. note how quick limp comes into play.. note if the temp gauge starts to shoot up quickly. or if when you turn the bus on and first start it if the temp gauge already reads high (the dash gauge gets its reading from the computer in year 2000)


all that said, the EBPV EWO1 mentions can drag down the engine. as its a flapper in the exhaust which is designed to help the engine warm up in cold weather.. if it sticks closed the symptoms are weak acceleration and bogging.. but you typically wont see codes as the T444E doesnt have a backpressure sensor...

[nikitis]

My 2 cents based off of those codes is check coolant levels, then if that doesn't work, replace the thermostat. Rule those out.

[SkullGirl]

Ok...I just found out I had some miss information...it is a 2000 International 3800 7.6 DT466. Does that make a difference.

Coolant level is good

[ewo1]

Originally Posted by SkullGirl

Ok...I just found out I had some miss information...it is a 2000 International 3800 7.6 DT466. Does that make a difference.

Coolant level is good

Omg…. Yes, it makes a difference.

To learn a little about gas pedal sensor -> https://www.skoolie.net/forums/f37/a...ine-42296.html

[nikitis]

Originally Posted by SkullGirl

Ok...I just found out I had some miss information...it is a 2000 International 3800 7.6 DT466. Does that make a difference.

Coolant level is good

If the Coolant level is good, then after running it for 5 mins, carefully open the reservoir, it should be really hot and maybe under some pressure, so be careful opening it. Use gloves + rag so you don't burn yourself. If the Coolant is cool still however it may not be flowing and could be an issue.

If it's warm or hot, then it's flowing, and it may be a bad sensor/thermostat.

[SkullGirl]

Coolant is hot
Just cleaned the accelerator pedal with position sensor with electronic cleaner (it was really dusty). Went for a drive...it got up to 40 mph...wouldn't go more.

[nikitis]

Ok, if it's hot then there's a good chance the engine is not actually overheating, but the sensor thinks it is. That heat has to come from the engine, so it has to be flowing. Might need to replace a thermostat somewhere. Not sure where as I'm only partially mechanically inclined.

[ewo1]

Originally Posted by SkullGirl

Coolant is hot
Just cleaned the accelerator pedal with position sensor with electronic cleaner (it was really dusty). Went for a drive...it got up to 40 mph...wouldn't go more.

Do you have access to servicemaxx ?

[cadillackid]

Originally Posted by SkullGirl

Coolant is hot
Just cleaned the accelerator pedal with position sensor with electronic cleaner (it was really dusty). Went for a drive...it got up to 40 mph...wouldn't go more.

coolant is hot... what does that mean? are you sure the engine is not overheating for real?

T444E or DT466E doesnt matter they use basicly the same control system...

[SkullGirl]

No I don't have access to servicemax.

It isn't overheating.