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08-06-2024, 10:00 PM
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#41
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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here's what mine looks like...only one little red light in the corner of the mode button comes on when holding that button long as you like.
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08-06-2024, 10:09 PM
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#42
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by Peterjk
Yes, I figured too. I didn't reset it, I don't know how. I didn't understand those directions you provided.
1. press and hold the MODE button for about 10 seconds: <<<nothing changes, just red light
2. Ensure the ignition is on but the engine is off <<Yep
3. Use either a push-button or lever shift selector<<I have a push-button
4. Enter Oil Life Monitor mode <<<Dont know how ??? See step 1
5. Press and hold the MODE button for about 10 seconds <<Nothing changes
6. Release the MODE button
The only thing that changes by pressing Mode iis a little red light lights up in the corner of that button. Not sure what its for.
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holding the Mode button for 10 seconds should clear any inactive codes in the TCM.
The link for the you tube video is another method. a friend of mine shared that with me after their 2000 tranny check trans light went on.
I never tried this method so best to watch the video.
If you know where the TCM fuse is, take it out and replace, see if engine accelerates. probably won't but at least your doing some easy, free troubleshooting.
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08-06-2024, 10:36 PM
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#43
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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RE:
holding the Mode button for 10 seconds should clear any inactive codes in the TCM.
Then its done, no change.
OK, Im going to call it an evening. Tomorrow, Im getting towed again to a real Cat dealer, provided they have time to see me, Ill find out at 0600, Boyd Cat.
Another 800$ iin towing for 22 miles, sigh.
But Id rather have Cat look at this issue then these guys here, my confidence dropped when they didnt feel like troubleshooting and just wanted to go for a ECM swap.
Night! Thanks again! Ill update this saga tomorrow. Money will be spent. But the trough will come out, hopefully its not a 20 cent part that caused this.
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08-07-2024, 08:03 AM
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#44
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Bus Nut
Join Date: Oct 2018
Location: Central Alabama
Posts: 653
Year: 1998
Coachwork: Blue Bird
Chassis: TC/2000
Engine: 5.9 Cummins 12-valve
Rated Cap: 1
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I'm with ck with it being the brake switch more than an issue with the tcm/ecm. Very few threads end with "replaced the ecm and everything works now" Good luck!
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08-07-2024, 08:15 AM
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#45
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Bus Geek
Join Date: May 2009
Location: Columbus Ohio
Posts: 19,850
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
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yeah im not big on just replacing parts to replace parts.. I dont know enough about CAT to know if there is a parameter that says dont let the pedal work if the J1939 link goes down..
I wasnt aware till reading the latest that the transmission pad was not working either.. it seems its getting at least one of its power leads if the red lamp comes on.. at this point it might be time to find a shop thats not only CAT but also allison.. or at least has allison DOC and can see if the TCM is even communicating..
I could see the ECM being a culprit if the Pins on the J1939 have one of them shorted to ground or open internally.. but the datalink CAN was desaigned from the ground up to be a very resilient system for industrial networks..(automotive mainly) its not fragile.. it resembles RS485.
the ECM sees the TPS input so id thinl some sort of inhibit is in play..
the transmission keyboard and pedal should be ablke to function on their own without the engine.. not for normal driving.. but the data wiring is a bus line.. think of 2 wires (road lanes.. one each direction).. with stops along the way.. each stop has a number... the little busses travelling with their data destined for the stop they wish.. so if stop 1 is the main depot (ECM).. stop 2 is the allison (TCM) and stop 3 id the allison keypad(shifter pad).. and you close stop 1.. the busses destined to go from the keyboard to the TCM and from the TCM to the keyboard still work.. (should still get a digit display).
I do know that the allison TCM and the Keyboard require both the BAT+ (all the time power) and the IGN+ (power with key) to fully come online and talk.. when turning on my bus I note that my check trans light comes on for a couple seconds then goes off.. if I unplug the BAT+ fuse but leave the IGN+ fuse in , then turn the key on, i dont get the check trans light.. and I wont see TCM on the J1939 in my scan tool.
if I unplug the IGN+ fuse then of course I dont see the TCM either and it doesnt talk.. as the TCM assumes the key is still off..
if my TCM boots up and the J1939 network is dead, when I shift to drive I get a check trans light immediately... (obviously you cant do this since your keyboard is not coming up)..
im just tossing these ideas out.. if i were a shop troubleshooting this id proibably first plug in a scan tool capable of seeing both engine and trans.. and see if the trans even shows up on the network.. , if it didnt, id be inclined to unplug the datalink from the ECM and see if the trans comes up on its own without the ECM in the network...
if still no trans then id start by checking power and ground at test points of pins on the TCM connectors.. (im sure CAT is like IH and has procedures for unplugging the connectors and testing for voltages in the various connectors..
the parts cannon guys scare me... now if he just happens to have a spare ECM laying around and its quick to try, and has the Cat ET software to proigram it for your VIN, then thats one thing.. (its important to remember just plugging in a new ECM can still result in lots of errors unless its been flashed to your VIN..).
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08-07-2024, 08:20 AM
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#46
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Bus Geek
Join Date: May 2009
Location: Columbus Ohio
Posts: 19,850
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
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Quote:
Originally Posted by BamaBus
I'm with ck with it being the brake switch more than an issue with the tcm/ecm. Very few threads end with "replaced the ecm and everything works now" Good luck!
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of course anything electronic CAN go bad.. but in an allison group im a member of, the same discussion gets brought up often.. everyone is ready to just swap a TCM when something throws an electronics related code.. allison has had issues with certain TCMs dying.. but generally they were 4th gens in GM vehicles.. the 3rd gen stuff like in the OP bus were really really solid.. the 4th gen used in the medium duity were also really solid..
I have hardware failures in the field like anyone does but we can almost always attribute our IT-related hardware failures to some type of an event.. (lightning, power failures, water, etc)...
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08-07-2024, 09:35 AM
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#47
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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I didnt get the impression his push pad was inop.
It lights up, displays the gear, no cats eyes.
He indicated it was able to go or at least display “R” for reverse.
The reset with the mode button made the red light go on.
I’m thinking, hoping its nothing but a corroded wire(s) somewhere.
Who know maybe faulty grounds ?
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08-07-2024, 10:07 AM
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#48
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Bus Geek
Join Date: May 2009
Location: Columbus Ohio
Posts: 19,850
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
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oh got it.. I was thinking he just had the red light and that was it..
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08-07-2024, 10:43 AM
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#49
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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J1939 data link 4th gen - troubleshooting
We all have data link on our busses and I'm sure it is widely misunderstood on how it's built and how it interacts with the engine computer.
Here is pages 727-736 of the Allison trouble shooting manual that explains troubleshooting in a straight forward manner.
Page 731 talks about and explains what the terminating resistors are and what they do.
If yo got a bus you should at the very least print this and keep it in your bus, not at home...you never know when something is gonna happen!
@Peterjk,
I hope it turns out to be something simple and cheap!
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08-07-2024, 11:03 AM
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#50
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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Morning all!
Just catching up reading here. Thank you all for pitching in, goes without sayiing, this group is the best.
This morning the shop manager stopped by to talk to us, he didnt realize we were in the parking lot staying in the bus! LOL
I explained what I heard from his mechanics yesterday.."replace the ECM/hope for the best"
He called BS on that troubleshootiing course of action too.
Now I feel better.
I also called Boyd Cat, they are still looking for a remote suport truck, that can stop by to assist. The local manager here said cool with that, the more people looking at this the better.
So things are looking up.
There are NO CODES to see other then the one I posted, its like the ECM says were all good, you should be driving.
RE what you all mentioned about
"I didnt get the impression his push pad was inop.
It lights up, displays the gear, no cats eyes.
He indicated it was able to go or at least display “R” for reverse."
The answer is yes, when I press R or D, you feel that the bus allison engages, it wants to go, just needs a little diesel. The TPS shows my throttle position, but nothing happens.
Last night I did crawl under the bus and reseated all 4 of the allison TCM plugs, they all looked good.
My "feeling" is, because we drive such a bumpy IN road to get to KY, somethiing shook loose, but the ECM isnt seeing it.
Anyway, Im waiting on BOYD CAT to call me back to get another set of eyes on this, without any codes or a CAT ET its difficult.
My bet iis also it will be something super simple.
Question, IF the ECM says were all good, but the mechanical governor isnt being opened to provide more diesel, where would thee disconnect be. Meaning, is it possible for the governor to be mechanically disconnected from thee ECM without the ECM showing the disconnect.
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08-07-2024, 11:04 AM
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#51
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by cadillackid
what about a brake switch? I remember once on a bidget rent a truck.. a freightliner FL70 from like 2001.. (no idea what engine).. it did the same thing and the issue ended up being that the computer thought the brake pedal was pushed when it wasnt.. so it wouldnt allow any throttle..
most of these trucks have 2 brake pedal switches.. not sure about your bus... just a thought...
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I was doing more research (learning) because I wanted to find out more about your mention of the brakes.
I just learned that the ABs IS also tied to and communicates on the datalink. It would be real interesting to see if at the end, it was the braking system....
I found this Allison training doc and on page 47 it has a real good diagram of all the interaction going on within the data link and also identifies where the terminating resistors are.
What I find curiously interesting is that there is a data stub that goes to the engine controller. it reflects 3 wires. could this be the section of the data link that goes to the ECM? or is there another engine controller in play?
I share this for those who wish to learn more...
snap, can't upload, 3.9 megs...
Here's the link --> https://rawze.com/forums/uploads/201...3f5ccad9bd.pdf
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08-07-2024, 11:18 AM
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#52
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by Peterjk
Question, IF the ECM says were all good, but the mechanical governor isnt being opened to provide more diesel, where would thee disconnect be. Meaning, is it possible for the governor to be mechanically disconnected from thee ECM without the ECM showing the disconnect.
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Really good question.... The TCM see the pedal response, you have verified that.
So from that point forward, how does the engine actually increase rpm??
@Cadillackid,
you just refreshed my mind about something... my bus has a wheelchair lift and you must stomp on the brake pedal in order to di-engage the air brakes to drive.
the wheelchair lift interlock can be turned off either thru Allison Doc or shorting out two wires on the TCM in order to TELL the TCM the input port is closed. On my Amtran if the lift is activated it will not go into gear, the push pad just flashes when you try to go into gear...this is with the lift sensors disconnected from the tCM wiring (port open/no signal).
Your mention of the brake switch along with busses having air brake "interlock". If any wiring /pins shorted out or opened within the TCM input ports, could possibly trick/tell the computer not to apply/increase RPM ???
Bus would still go into gear but no throttle response!
@Peterjk, when the bus is in neutral, does the pedal /engine respond like it should ???
also, out of more curiosity, see if the mechanics can look at the i/o prts of the TCM and verifiy if a port that is "open" maybe it is missing it's input signal.
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08-07-2024, 11:37 AM
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#53
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Bus Geek
Join Date: May 2009
Location: Columbus Ohio
Posts: 19,850
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
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Quote:
Originally Posted by ewo1
Really good question.... The TCM see the pedal response, you have verified that.
So from that point forward, how does the engine actually increase rpm??
@Cadillackid,
you just refreshed my mind about something... my bus had a wheelchair lift and you must stomp on the brake pedal in order to di-engage the air brakes to drive.
the wheelchair lift interlock can be turned off either thru Allison Doc or shorting out two wires on the TCM in order to TELL the TCM the input port is closed.
Your mention of the brake switch along with busses having air brake "interlock". If any wiring /pins shorted out or opened within the TCM input ports, could possibly trick/tell the computer not to apply/increase RPM ???
Bus would still go into gear but no throttle response!
@Peterjk, when the bus is in neutral, does the pedal /engine respond like it should ???
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so there is no mechanical pump governer on these like there are the older mechancal engines..
these CAT 3126, C7, T444E, DT466E, VT365 all use the same type of injection system..
you have a fuel lift pump that brings fuel from the tank rails in the heads (after filters and pressure regulator).. if that fails the engine wont even idle.
you have a regular oil pump.. (on IH its on the crank..) its the lube il and is what registers oil P on the dash gauge.
you have a High pressure OIL pump (note oil, not fuel). which is controlled by the ECM and via a valve.. the sensor which tells the ECM the pressure is the ICP, the valve which phyiscally controls this High pressure is the IPR.. the ECM sets the PSI it needs...
then you have injectors which have solenoids in the that when actuated by the computer open up the high pressure oil to the plunger ..the plunger pushes the fuel down into the cylinder.. how often and how long the plunger plunges is controlled by the ECM..
so if you want a lot of fuel quickly the HPOP pressure goes up higher.. slower progression of fuel runs a lower HPOP pressure which in turn sends fuel in slower..
the throttle pedal is nothing more than an RPM setpoint.. I have the curve for my IH noted.. each engine is different (and there are different maps).
all that said.. if the HPOP pressure was too low, the engine wouldnt just sit N idle.. it would likely stumble as the computer struggled with trying to getthe fuel in... same with low fuel pressure.. it would smoke, stumble, run rough etc when you pressed the throttle..
on IH when troubleshooting the pedal (remember im an IH guy not CAT).. the pedal has 5 wires..
3 of them are for the TPS position reading.. there is a +5 VDC, a sensor reading (return).. and a reference ground...
2 of them are an idle validation switch.. this is designed so that if the TPS were to read throttle input yet the pedal were on the peg (no foot) it would not run the engine up... on IH this sets an idle validation error code and you get dead pedal.. (the computer sees TPS % but also sees the pedal should be on the peg so it errors on safety and doesnt run up the engine).. its a conflict..
part of me wonders if CAT has the same Idle validation switch and doesnt set a code... its something to look at to see if CAT uses the same 5 wire pedal...
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08-07-2024, 11:39 AM
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#54
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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RE:
Really good question.... The TCM see the pedal response, you have verified that.
So from that point forward, how does the engine actually increase rpm??
The TCM see the pedal response, you have verified that
YES, see my screenshots ^^^ also verified with their scan tool, not cat ET.
So from that point forward, how does the engine actually increase rpm??Fly by wire Im told
RE:
@Peterjk, when the bus is in neutral, does the pedal /engine respond like it should ???
NO. Pedal does not respond at all.
ScanGauge does, shows throttle position to match the pedal position.
Wheel chair lift issue from the shaking we had, yes entirely possible I suppose.
r
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08-07-2024, 11:43 AM
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#55
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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When I purchased the bus we had a wheel chair lift the bus resale company removed and disconnected the wire.
Its taped up underneath the bus, I know where it is, just FYI. Could that be the culprit ?
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08-07-2024, 11:45 AM
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#56
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by Peterjk
RE:
Really good question.... The TCM see the pedal response, you have verified that.
So from that point forward, how does the engine actually increase rpm??
The TCM see the pedal response, you have verified that
YES, see my screenshots ^^^ also verified with their scan tool, not cat ET.
So from that point forward, how does the engine actually increase rpm??Fly by wire Im told
RE:
@Peterjk, when the bus is in neutral, does the pedal /engine respond like it should ???
NO. Pedal does not respond at all.
ScanGauge does, shows throttle position to match the pedal position.
Wheel chair lift issue from the shaking we had, yes entirely possible I suppose.
r
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Ok but do you have a pedal/engine response in NEUTRAL ?
So far you only mention that when you put it in gear, no throttle.
Just curious to know if the no throttle happens in both neutral and in gear or only when in gear?
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08-07-2024, 11:50 AM
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#57
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by Peterjk
When I purchased the bus we had a wheel chair lift the bus resale company removed and disconnected the wire.
Its taped up underneath the bus, I know where it is, just FYI. Could that be the culprit ?
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I replaced the 5 spd TCM in my '99 Amtran with a 6 spd TCM from a 2005 Amtran. the 2005 had a lift, the '99 did not.
That's when I started learning about I/O ports on the TCM.
It would not go into gear and no throttle response, in my situation.
2 choices I had, close the port using Allison doc, dealer wanted $400 bucks.
Or just short out two inputs on the TCM which in turn tells the TCM port is closed. I shorted the two pins, that was $$$ FREE $$$.
Can't say if this is your problem but the info is for sure worth knowing about, I/O ports that is.
Usually no discussion here about that but it IS part of the real bus world!
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08-07-2024, 12:01 PM
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#58
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Bus Nut
Join Date: Jul 2020
Location: Great Lakes
Posts: 339
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Cat C7 300/800
Rated Cap: 31
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FOUND THE PROBLEM!!!!!!
Because of the severe road shaking, my wheel chair door safety cutout for the ground wire of the ignition came loose, so door became closed.
Door needs to be unlocked to move.
I would never have found it if you hadnt mentiond WHEELCHAIR
WOOOOO, thank you all, were leaving momentairly.
Peter ))
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08-07-2024, 12:03 PM
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#59
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Quote:
Originally Posted by Peterjk
FOUND THE PROBLEM!!!!!!
Because of the severe road shaking, my wheel chair door safety cutout for the ground wire of the ignition came loose, so door became closed.
Door needs to be unlocked to move.
I would never have found it if you hadnt mentiond WHEELCHAIR
WOOOOO, thank you all, were leaving momentairly.
Peter ))
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Woo hoo !!!
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08-07-2024, 12:08 PM
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#60
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Bus Crazy
Join Date: May 2015
Location: Central Tx.
Posts: 2,422
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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FYI
post #153 of my 9906 build thread, you'll see how I spliced my wires together right at the TCM, well 6 inches away...
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