Weird no throttle problem

[Highwaysunshine]

Hey everyone im new to the forum but could really use some advice. 2001, international t444e. Driving on a bumpy dirt road all the sudden the throttle stops working and there is a warning engine light. The engine still runs but nothing happens when i hit the throttle. Turn it off, and back on, and it runs, and the throttle works, however now even the slightest bump will kick the bus back into that mode. What might this be and how do i try to pull a code from the dash with no code reader? Any advice would help. Thanks a lot

 

[BamaBus]

You need EGES 125
https://www.skoolie.net/forums/f13/t444e-wiring-problem-38990.html#:~:text=https%3A//www.google.com/url%3Fsa%3Dt%26rct%3D...NXFx%2DaO0oAZThU
The above copy is not as clear as the copy I have but I don't know where I got mine.

See Section 1.9 page 2 for the sequence to check the codes using the "STI" button located beside the round data port, normally under the dash.

This post has other pdfs that will help but I believe you will need a microsoft acct.
https://www.skoolie.net/forums/f37/international-engine-manuals-40297.html

There is a video here that shows reading the code but doesn't explain the difference between the code 111(the one you want) and the inactive codes that are listed.

https://www.skoolie.net/forums/f49/vpm-question-43945.html

 

[BamaBus]

Ultimately, I believe its going to be the "Loose wire/Bad connection" reason for a failure. A loose connector going to a sensor or a bad ground wire is causing the ecm to lose communication and its reaction is to throw a code and prevent you from driving any further. It could also be a bad connection to accelerator pedal itself. Bouncing up and down while the foot is on the accelerator could be causing and issue.

 

[nikitis]

You need EGES 125
https://www.skoolie.net/forums/f13/t444e-wiring-problem-38990.html#:~:text=https%3A//www.google.com/url%3Fsa%3Dt%26rct%3D...NXFx%2DaO0oAZThU
The above copy is not as clear as the copy I have but I don't know where I got mine.

See Section 1.9 page 2 for the sequence to check the codes using the "STI" button located beside the round data port, normally under the dash.

This post has other pdfs that will help but I believe you will need a microsoft acct.
https://www.skoolie.net/forums/f37/international-engine-manuals-40297.html

There is a video here that shows reading the code but doesn't explain the difference between the code 111(the one you want) and the inactive codes that are listed.

https://www.skoolie.net/forums/f49/vpm-question-43945.html

I sent you a Private Message BamaBus

 

[ewo1]

Take a look at the gas pedal, there should be a sensor there. Did the connection get loose to the sensor ?

 

[Highwaysunshine]

Take a look at the gas pedal, there should be a sensor there. Did the connection get loose to the sensor ?

I did wiggle that connection and nothing happened. Im going to check on the wiring harness tonight when i get the chance

 

[cadillackid]

there are 5 wires going to the "gas" pedal. 3 of them are the sensor wires that tell the computer what position the pedal is in by returning a voltage back.


the other 2 wires are a switch that tells the computer when the pedal is fully returned (idle). or if the oedal is being pressed..


the idea being that these are chack and balance... if the pedal reads that its being pressed but he switch tells the computer the pedal is in idle position.. the computer opts for the safety which is to not use the position.. and instead sets a code and shuts down the pedal for that key cycle..



ita pretty common when the pedal goes bad for the switch or the sensor to go erratic.. the codes in the computer will tell you whether the switch or the pedal sensor is faulting.. once we know the code we can look to diagnose it...



the EGES-125 diagnostic manual is technically for. the 3 box system however testing for a bad pedal or wire is the same.. I think I have the later manual in my OnCommand id have to look it up if the linked manual doesnt work.

 

[ewo1]

there are 5 wires going to the "gas" pedal. 3 of them are the sensor wires that tell the computer what position the pedal is in by returning a voltage back.


the other 2 wires are a switch that tells the computer when the pedal is fully returned (idle). or if the oedal is being pressed..


the idea being that these are chack and balance... if the pedal reads that its being pressed but he switch tells the computer the pedal is in idle position.. the computer opts for the safety which is to not use the position.. and instead sets a code and shuts down the pedal for that key cycle..



ita pretty common when the pedal goes bad for the switch or the sensor to go erratic.. the codes in the computer will tell you whether the switch or the pedal sensor is faulting.. once we know the code we can look to diagnose it...



the EGES-125 diagnostic manual is technically for. the 3 box system however testing for a bad pedal or wire is the same.. I think I have the later manual in my OnCommand id have to look it up if the linked manual doesnt work.

I had a similar situation not to long ago and thanks to Cadillackid I not only
learned how the system works but also fixed my problem.

Take a look at posts #11 and #17 of this thread that I started. You will find 2 PDF files that will help you understand some more.

Basically the 2 circuits within the pedal sensor, one is a potentiometer that will send a reference voltage depending on the pedal movement to the ECU. This reference voltage is how the computer knows when to speed up the engine.
you can test this function with an ohmeter.

the second circuit is basically a hall effect sensor or basically an ON/Off switch. when you step on the pedal this circuit signals the ECU that it is ok to speed up the engine.
You cannot test the hall effect with an ohmmeter but you can test with an oscilliscope.

Easiest way to test if it is your sensor or not is to swap it out with another known good unit, from another vehicle with a similar engine as yours. don't worry too much about the model year, this is only a test.

Your not gonna find an OEM replacement cheap but remember this, all these sensors come from china or taiwan anyways!

You can buy a DORMAN replacement but they are very costly and forget about going to the dealer.

In that thread I posted I believe I listed the source where I got mine real cheap, even bought an extra to carry as a spare.

You can also just start the bus and starting from the ECU, wiggle/firmly tap the wiring harness and follow it back best you can to the pedal.
From what you posted I am inclined to think yours night be a loose connection or wires rubbing/chafing somewhere along that harness.

 

[cadillackid]

I had a similar situation not to long ago and thanks to Cadillackid I not only
learned how the system works but also fixed my problem.

Take a look at posts #11 and #17 of this thread that I started. You will find 2 PDF files that will help you understand some more.

Basically the 2 circuits within the pedal sensor, one is a potentiometer that will send a reference voltage depending on the pedal movement to the ECU. This reference voltage is how the computer knows when to speed up the engine.
you can test this function with an ohmeter.

the second circuit is basically a hall effect sensor or basically an ON/Off switch. when you step on the pedal this circuit signals the ECU that it is ok to speed up the engine.
You cannot test the hall effect with an ohmmeter but you can test with an oscilliscope.

Easiest way to test if it is your sensor or not is to swap it out with another known good unit, from another vehicle with a similar engine as yours. don't worry too much about the model year, this is only a test.

Your not gonna find an OEM replacement cheap but remember this, all these sensors come from china or taiwan anyways!

You can buy a DORMAN replacement but they are very costly and forget about going to the dealer.

In that thread I posted I believe I listed the source where I got mine real cheap, even bought an extra to carry as a spare.

You can also just start the bus and starting from the ECU, wiggle/firmly tap the wiring harness and follow it back best you can to the pedal.
From what you posted I am inclined to think yours night be a loose connection or wires rubbing/chafing somewhere along that harness.

+1 on it sounding like a wiring issue.. wouldnt be the first time ive seen the rubber grommets wear out where the harness goes through the firewall.. and also another thing that happens is the pins get corroded on the pedal wiring connector from wet boots / shoes or if the bus has a water leak that periodically drips on the pedals... will cause things like this..

 

[skoontz]

I had a similar lose of power when I bought my bus, but neither me nor the mobile mechanic could replicate it when the bus was at his shop. Would up replacing the wires from peddle to engine, and the problem hasn't come back

 

[Highwaysunshine]

Ok i finally got to poking around with it. Replaced the TPS and nothing. Also, now the problem has gotten to the point that as soon as i turn the key, the engine light flicks on and offf like normal, but the light comes back in a few seconds weather i start the truck or not, and when i start it. The throttle does nothing at all. It will shift into drive or reverse and idle forward or backward but thats it. Im starting to think its something different thats forcing the truck into limp mode but i have no idea what it is. How do I make this thing flash the codes?

 

[ewo1]

Ok i finally got to poking around with it. Replaced the TPS and nothing. Also, now the problem has gotten to the point that as soon as i turn the key, the engine light flicks on and offf like normal, but the light comes back in a few seconds weather i start the truck or not, and when i start it. The throttle does nothing at all. It will shift into drive or reverse and idle forward or backward but thats it. Im starting to think its something different thats forcing the truck into limp mode but i have no idea what it is. How do I make this thing flash the codes?

I wouldn't be too concerned about codes right now as I am sure their will be a code for the TPS circuit showing.

Take a step back and look at what you wrote before:

however now even the slightest bump will kick the bus back into that mode.

That statement right there is clearly indicating you got wiring issues.

Did you take a look at the wiring diagram I pointed out to you?
That diagram is is for a T444E and it applies to your bus!

It is not uncommon to find frayed wires or connections turning green and creating poor contact.

The fact that with any slight bump in the road the throttle would die is telling you something.

Fortunately this is not rocket science... It is a bit time consuming but follow the wires from the pedal back to the ECU. look for places where the wire harness might rub against something like an oil filter for example.

Even if you don't SEE a broken or chafed wire, don't be afraid to open up the wire looms and take a closer look, especially anywhere the harness lays/rubs against metal.

If your gonna stay in the SKOOLIE game then you gotta to start learning how to fix your bus, so go get it done!

 

[BamaBus]

How do I make this thing flash the codes?

Is that a serious question?

 

[Highwaysunshine]

Yes that was a serious question but i figured it out.
Update: started pulling into the wires, havent found the root cause yet but i did find they are smashed pretty well between the dash and steering colum, and that seems like the hot spot for where the short is likely to be. I switched some relays around and the bus managed to turn on and drive normal for about 10 minutes before it kicked itself off again and the problem seemed to restart like before when i could drive it for a bit before it would kick itself off.

The codes i pulled
113 ECM PWR
Electrical System Voltage B+ out of range LOW
131 APS/IVS
Accelerator Position Signal out of range LOW
134 APS/IVS
Accelerator Position and Idle Validation disagree
135 APS/IVS
Idle Validation Switch circuit fault
152 BARO
Barometric Pressure Signal out of range LOW
325 ECT
Power reduced, matched to cooling system performance
626 ???

 

[ewo1]

Yes that was a serious question but i figured it out.
Update: started pulling into the wires, havent found the root cause yet but i did find they are smashed pretty well between the dash and steering colum, and that seems like the hot spot for where the short is likely to be. I switched some relays around and the bus managed to turn on and drive normal for about 10 minutes before it kicked itself off again and the problem seemed to restart like before when i could drive it for a bit before it would kick itself off.

The codes i pulled
113 ECM PWR
Electrical System Voltage B+ out of range LOW
131 APS/IVS
Accelerator Position Signal out of range LOW
134 APS/IVS
Accelerator Position and Idle Validation disagree
135 APS/IVS
Idle Validation Switch circuit fault
152 BARO
Barometric Pressure Signal out of range LOW
325 ECT
Power reduced, matched to cooling system performance
626 ???

Confirmation on my thoughts that your problem is electrical!

ECM losing power, loose wire somewhere!!!

all the other codes are TPS related.

I'm gonna ask you again if you took a look at the wiring diagram I posted in the other thread... WHY ???

Well you will see that the TPS is feed by a fuse. I would start by locating that fuse, pulling it and see if the legs of the fuse are discolored.

I had a TCM issue where it was resetting while driving causing me to fear that my tranny was gonna die.
turned out to be a worn out fuse holder.

Once you locate the fuse, check the wiring in that area. I would go as far as grabbing the bundle of wires at the fuse location and shake them up real good to see if you can reproduce your issue.

ECM resetting could either be you disco the batteries or pulled the ECM fuse. If not any of those scenarios then maybe a bad ground or hot (12v) wire to the ECM!

Another great example of wiring issue, I have fixed 4 Allison dead key pad issues so far, all due to broken wires. Twice it was in the waterproof connector itself.

see post #2, in this thread..

Take a look at post #48, in this thread...


Another loose / poor / failing connection that get's easily overlooked !!!

 

[BamaBus]

Yes that was a serious question but i figured it out.
Update: started pulling into the wires, havent found the root cause yet but i did find they are smashed pretty well between the dash and steering colum, and that seems like the hot spot for where the short is likely to be. I switched some relays around and the bus managed to turn on and drive normal for about 10 minutes before it kicked itself off again and the problem seemed to restart like before when i could drive it for a bit before it would kick itself off.

The codes i pulled
113 ECM PWR
Electrical System Voltage B+ out of range LOW
131 APS/IVS
Accelerator Position Signal out of range LOW
134 APS/IVS
Accelerator Position and Idle Validation disagree
135 APS/IVS
Idle Validation Switch circuit fault
152 BARO
Barometric Pressure Signal out of range LOW
325 ECT
Power reduced, matched to cooling system performance
626 ???

Good to see the codes!

From what I see the 131,134,135 codes are the one to allow the engine to run but without throttle response. The thread here https://www.skoolie.net/forums/f37/t444e-throttle-gas-pedal-electrical-problem-question-42081.html POST 11 from cadillackid, list a part on the accelerator that is replaceable without replacing the entire assembly. They can be found for $20 and up.
There is this, https://static.nhtsa.gov/odi/tsbs/2014/SB-10044293-1044.pdf, among other things, it describes pulling up on the pedal to create a fault determining if the pedal itself is bad.

Some of the other codes may cause loss of power or engine shut down. 113 could be an alternator issue. From manuals on the T444E and DT466E:

"Code 113 can be caused by consistently less than 6.5 volts being applied to ECM terminals 37 and 57. This can be caused by a defective alternator, low
batteries, and/or increased resistance in the battery feed circuits. Code 113 does not turn the Engine Warning Light ON."