Had just merged with traffic on my way home. Suddenly had no power, coasted to a stop on shoulder. Gauges were all dead, including the tack, but the engine was still running and the transmission shifter was live, showed the 6 - 1 thing. I shut off key, engine died (of course) turned key back on, no gauge or transmission lights. Turned key off and on again and everything was back to normal. Started up and drove home (60 miles).
I did a tranny diagnostic check when I got home, got the following 3 readings: O L, - -, and 5 0 (this 0 being a number).
Any ideas????
Would start at the connections (hot and ground) for the engine batteries, isolator, ignition solenoid. Use test light (good) or digital meter (better). If you can't find the problem right away, take the electrical schematic and have it blown up to blueprint size. Will be MUCH easier to read.
Bad/intermittent ground fault could also cause transmission codes.
Hope this gets you started. Others may have had this happen.
Ignition relays on bottom of circuit breaker panel in front of copilot. Sometimes there are two relays that power the breakers that are hot with ignition key. With meter some breaker buss bars may be dead when they should be hot with ignition key on.
Thanks for the reply's. I'm going to make a couple of assumptions. 1. the transmission isn't the culprit. 2. Intermittent problem is going to be difficult to find.
BUT, would the fact that turning the key off and on "fixed" it, would we more inclined to think it was relays getting reset?
Gayland,
But, since the transmission shift pad stayed "live" that would rule out the ignition switch and ignition solenoid UNLESS the voltage drop across the solenoid (from burned points) was sufficient to still power the transmission ECU, but not sufficient to power other functions.
I would start by wiring a digital voltmeter from the "only when ignition on" large lug of the ignition solenoid to ground and checking voltage when this occurs.
And, as always, verify that all connections, particularly ground connections are tight and clean.
Brett
Per the Allison Shift Selector Code manual lists your code when "Checking" Fluid levels as a Fluid Level Fault Description Engine speed too low
Give me a call if you have any questions 410-877-4816
Tony
Tony - I've been having internet problems tonight so haven't been able to look for the codes yet. I did the diagnostic check like you said, got the code 1221, which isn't any of those you had gone through. Could you look it up please. It only came up with the one.
When my ECU failed I contacted Transmission Instruments (easy to find on the internet). I think Brett posted about him. He told me that my generation of ECU (maybe yours too) is notorious for having the internal power supply fail which can manifest in many ways. I think I actually had a code for ECU failure and the alarm wouldn't stop but it never actually stopped working though Allison told me that it would shift into the next lowest gear and lock until the coach was powered down then it wouldn't start again. They wanted to sell me a new one for several thousand dollars. Transmission Instruments had me send him the ECU and control panel, he replaced the power supply, tested it after heating and cooling it to extremes and sent it back. He said that if it fixed the problem...send him $300. Best money and process on a reapair since I've owned this coach. It did fix the problem. I had been getting a code for turbine speed sensor off and on causing the transmission to stay in 1st gear until it heated up (which it did with or without the code and alarm). That wasn't a cheap repair as the module had to be dropped to get to the sensor.
I discovered I'd transposed the code #'s, should have been 2112, which is a throttle position sensor failed, low. What ever that means!!! Anyway for now, I'm going to stick with the assumption that it's a ground or weak relay problem with the 12 volt system somewhere.
Now that you have the correct code I can direct you to the Transmission code manual.
Allison Transmission Codes Manual (http://beamalarm.com/Documents/allison_transmission_codes_manual.html)
Your problem is probably the ignition switch solenoid and can be caused by the pitting of the contacts or just having it fail (windings, corrosion, etc) due to age. I suggest that you make up a jumper wire with two alligator clips that will fit adequately clip to the nuts on your ignition switch solenoid. This will allow you to bypass the solenoid and get power through to the necessary components when you encounter the problem again. I am still carrying my jumper wire even though I replaced the solenoid.
The failure of the ignition switch solenoid can be caused by the pitting of the contacts or just having it fail (windings, corrosion, etc) due to age. It would be a good idea to purchase a good quality continuous duty solenoid and replace your existing one and not worry about it again.
I had mine fail at a traffic signal. Not fun.
FWIW,
Regards,
And here it is: Cole Hersee 24143 for about $50. Best to have a couple handy as the boost solenoid is the same. Continuous duty with silver contacts. Most truck stops should have it but NAPA can get it in a day but will cost $10 more. Photo below. Note: Cole Hersee has replaced the 24143 with a new solenoid, the 24213. See at: Solenoids & Relays | Steel & Phenolic Body Solenoids | Continuous Duty, SPST | (http://www.colehersee.com/home/item/cat/174/24143/)
The 24213 has silver tungsten carbide contacts (better), but is electrically identical.
Thanks, I will definitely do the replacement. I'm also going to check more on the throttle position code I got to find out if it can cause similar symptoms.
My only concern in trying to duplicate the problem without changing the solenoid is doing it with current flowing and having an interruption that may cause a momentary voltage spike that the transmission computer will not like. A spike may possibly have caused the throttle position code to show up (or not) as well as the other codes. Should also check to see if the solenoid is getting a good ground at the both the solenoid and the other end of the grounding wire where it goes to the chassis.
2 solenoid's ordered from RyderFleetProducts, $90.63 including shipping. I won't be using the coach anymore this year, unless we have another month of nice weather. Not likely here in ND.
OK my turn in the barrel. Drove from Ajo to Tombstone and as is my normal mode of operation did not turn the coach of until I got to the campground. Everything was normal all day. Parked the coach and turned off the engine. Thought I'd back up a couple feet but the shifter pad would not light up. I can start the coach with the boost switch on but still no light on the Allison shifter. Ideas?
Roland
Roland,
Scratching my head - got to be something electrical that changed or failed. Doing a Google search - will add links as I find them:
http://www.transmissioninstruments.com/troubleshooting.html
allison trans shift selector has blank display - Topic (http://www.barthmobile.com/eve/forums/a/tpc/f/3631087061/m/9491042361)
Just a WAG, but have you checked the chassis battery connections and/or unplug and replug the connector to the shift pad.
Roland,
In my Google search, I keep seeing reference to a "fuse on the power supply lead" to the ECU. But I can't figure out where the trans ECU on our coach gets it's power! I've looked at both of my 12V wiring diagrams, and I don't see anything about the trans ECU.
Still searching...
Apparently a lot of SOB diesel coaches have a thing called the VIM (Vehicle Interface Module) and that's where the power fuse is for the Allison transmission ECU. I've never seen anything like that on my coach.
I don't know...I'm stumped.
You could try calling John Kopalek at Transmission Instruments tomorrow morning - see what he says. He rebuilt my shift pad and ECU 3 years ago when I was bit with the "snake eyes" malfunction. Been working great ever since.
Transmission Instruments Contact Information (http://www.transmissioninstruments.com/contact.php)
Or try getting hold of Triana at FOT (good luck with that).
Sorry I can't be more help.
Early pads were not sealed well.
Only thing I would be doing is to be removing and replacing the connectors at each end. 10 times was what John told me.
My only input. Wiggle the wires in essence
Is the salesman switch on?
Chuck,
Here is a link to pics. as to where it is on the M-11 engines. Some 8.3s are close to this same location. This is in the wire loom right where the engine and trans wiring split. Cummins M11 ECM Fuses (http://www.foreforums.com/index.php?topic=24498.msg191899#msg191899)
Mike
Roland,
Still same problem this morning, or did it "cure itself" overnight?
Why did you need your boost switch on (last night) when you tried to restart your engine? After driving all day, your engine batteries should have been at 100%. Does everything else work on your dash when you turn ignition switch on (with boost switch off)?
Very low voltage from start batteries might cause problems with the trans shift pad?
Thanks Mike. Since Roland's (and my) engine are pure mechanical and don't have a engine ECU, I'm not sure if they would bear any similarity to the electronic engines. I always kinda "assumed" that our Allison
trans ECU was powered directly off the ignition solenoid, but now I don't know, cuz it doesn't show up on my wiring diagram.
Didn't do anything to troubleshoot the problem last night. Going to work on the issue this morning after breakfast. Thanks to all the inputs from the Forum I have a place to start. Will begin with voltage measurements from the batteries forward. Will post. my findings. Will begin the process after a cup of coffee.
Roland
I'm unclear on the subject of ATEC (Allison Transmission Electronic Control).
Does the '93 U280 (Cummins C8.3 300HP mechanical engine with Allison 6-speed MD3060) have "ATEC"? Right in the middle of my 12V wiring diagram, there is a set of 5 wires and a box that says "TO ATEC DWG A-4845". Anyway, I don't have that drawing in my books. I thought I read somewhere that only the '93 U300 (DD 6V92 DDEC with HT746 trans) had ATEC, but I could certainly be wrong about that.
I also thought that ATEC was part of the electronic control package that was added to "electronic" engines in later years (post 1993).
Anybody know for sure which year/model/engine coaches actually had ATEC?
AND HAS ANYONE EVER FOUND A FUSED POWER WIRE GOING TO THE ALLISON ECU?
AND HAS ANYONE EVER FOUND A FUSED POWER WIRE GOING TO THE ALLISON ECU?
[/quote]
What I am looking for now. Found the spot where the wire loom breaks out for the transmission did not see any fuses there. Going to cut back on the electrical tape too see if it is buried.
Roland
Although mine is a 99 the fuse folders for mine are In The harness on top of the bell housing I beleave
There are three fuses under the dash for: AUX TRANS CONTROL, ATEC IGNITION, ATEC COMPUTER. Unfortunately they are all good. Did not find any fuses back at the transmission.
Roland
DANG IT! I just went out and popped our dash cover, saw those 3 fuses, and took pics of them. I was gonna tell you to check them.
Well, that doesn't help. I am still totally mystified where the power comes from for the transmission ECU and touch pad.
These are the photos I took of the harness breakout for my transmission. There are no fuses here that I can see.
Rolans
If all else fails, I've heard good things about these guys in Tucson. Allison Transmissions and Detroit Diesel Engines - Global Industrial Automatics (http://www.globaltranny.com)
Under the dash cover, the 10A fuse in the bottom left corner of the fuse chart labeled ATEC COMPUTER - I know you checked it to see if it was blown. But, is it hot all the time, regardless of ignition switch position?
It looks like that 10A fuse is powered from the battery side of the ignition solenoid, through one of the big round 90A circuit breakers located on the main 12V panel in the center storage bay (under the white fiberglass cover). From the 90A breaker it goes through a 30A ATEC circuit breaker, then back up front to the fuse block.
Battery voltage is 12.8 at the start battery and at the solenoid. I have started the coach repeatedly with no change. Unless someone with a 1993 U280 with a Cummins 8.3 mechanical engineer and a six speed Allison can identify any other fuses or voltages that I should check I am at the end of my ability to diagnose.
Roland
I just went out and checked our 10A fuse with a test light. It IS hot all the time, with ignition switch OFF. How about yours?
Roland, have you tried removing the chassis battery ground and wait a bit to see if it will reset?
I just checked that ten amp fuse under the dash and it is hot all the time. The other two fuses are only hot with the ignition on.
Roland
Yes and no difference in anything anywhere.
roland
May be the final solution.
Roland
Roland,
Did you try running the trouble shooting tests from the Transmission Instruments website? I'll link it again below. They would tell you if you are getting power to the ECU connector. If you are, and the touch pad still won't come on, then I'm afraid it is dead. See what you find.
Our coaches have the WTECII system (2nd paragraph).
http://www.transmissioninstruments.com/troubleshooting.html
Will give it a try.
Roland
I didn't see this mentioned in earlier posts. Have you tried reseating the Allison ECU input and outputs. The outputs are indicated with the arrows in the photo. The inputs are on the other end of the ECU.
jor
Also, here's a copy of the Allison wiring diagram for my rig which may match yours. Got it from Barry when I was having an issue. You can ID the 12v power wire coming into the Allison box to determine if you have power there. Probably do in that your fuse shows good. You can ID the output wire and check for power there.
You do what you think is best, but if it was me I would call John Kopalek at Transmission Instruments before going to any local shop. 9.9 times out of 10, the local Allison techs will just want to sell you a brand new touch pad or ECU (if they can even find one). Either part will be BIG bucks. John will fix the one you've got (or sell you a rebuilt unit) for a LOT less money. If he can't fix it, he will tell you - he is a straight shooter. And his turn-around is quick - usually only a day or two, plus the mailing time.
But like I said, you're in charge!
Guess I'm going to stay into stay in the barrel a while longer. I do not have the original ECU. My ECU was replaced in 05 and John can't fix it. Or very little chance that he can fix it. And as it was replaced wit a "new" unit I can't just slap an original computer in its place. Now I will have to deal with the Mfr or a dealer.......Gee Lucky me.
Roland
Global Trans in Tucson has a "transmission" section on their site you can click on. Click on "troubleshooting" and scroll down to "Main Code 23" and "Subcode 12" & "14". Could that be you? Allison Transmissions and Detroit Diesel Engines - Global Industrial Automatics (http://www.globaltranny.com)
Sorry! Hope you are parked in a nice spot and they aren't in a hurry for you to move.
Here in an RV Park in Tombstone until Thursday. Going to try and arrange a tow for Thursday as we may have a place to go while they work on the coach.
Roland
I know it sounds stupid but...... Take a hair dryer to the Tranny ECU. May get you going. Also I assume you have unplugged it, cleaned the contacts and reseated it.
Gary B
Roland, great food and drink at the Legion there, and the price is right!
Also, some gunfighters and barmaids there are from Maine originally.
Best of luck with your diagnosis and repair.
I spoke with John Kopalek, he's the one that repairs the original Alison computers, and he indicated that the replacement that I have is not sensitive to heat as the originals. I did remove the connectors and reseat them to make sure that wasn't the issue. The thing is dead as a doornail.
Roland
Which outlet are you taking the coach? Thank goodness you're only 70 miles from Tucson! ^.^d
This is the page I have for my 92 with ATEC not sure if it will help
Not sure yet haven't made arrangements.
Roland
Cant read codes with a dead unit. My shifter does not light up.
Roland
Roland, have you disconnected the connector at the shift pad and checked for voltage on the connector plug pins with the ignition on?
No and I should have done that. I thought about doing it, put it off then forgot. I got involved with something else and it completely slipped my mind. Will give it a shot in the morning.
Roland
Sorry, got on the wrong thread, someone else had the "cat's eyes" and subcode 12 & 14 mentioned those.
Hey Roland,
How you doing? Any update on your situation?
Not yet. Will be going to Tuscon today and will go to the Allison dealer there for a confab. Will keep y'all posted on my progress until I get it resolved as I don't like open ended threads.
Roland
Spoke with Richard Andrews at Arizona Transmission. I got a couple drawings from him that I have never seen before. There is, according to these drawings, a "VIM" unit between the ECU and the touch pad. And there are two 10 amp fuses inside this unit. Problem is I can't find this "VIM" unit. This sound correct to anyone?
Roland
I know you've been busy and probably didn't notice, but I mentioned the elusive "VIM" back in reply #18. I kept running across reference to it on other forums. If we have one of these boxes on our coaches, I sure haven't ever seen it. I don't think we do, but I could be wrong. One way you could check would be to test the continuity of the wire between the "always hot" 10A ATEC fuse (under your dash cover) and the power pin on the ECU plug. If the wire running from the ATEC fuse is the same wire supplying power to the ECU, then there must not be anything in between. Or at least if there is anything in between, it is not "blown".
Chuck, according to Richard Andrews the VIM unit should be next to the ECU. Sure not there on my coach. Going to overnight my ECU to John Kopalek tomorrow.
I find measure some voltage at the shifter input but was not the five volts that Richard claimed should be there. Would but a new ECU "IF" I was certain mine was bad. Don't have to get the coach towed to the dealer if I can identify the bad component. That's a relief. Campground here is willing to "work" with me.
Roland
Does anyone have an electrical diagram that includes the shift pad?
If one exists, I sure haven't seen it. It is easy to find Allison diagrams (online) showing the wiring between the trans ECU and the remote shift pad. Those are the same diagrams that show the mysterious VIM box. The problem is, when Foretravel tied the Allison transmission electronics into our early GV coaches, they apparently didn't bother to document the wiring circuits that were added to the coach. My Owner's Manual says I have a Allison MT 647 transmission, which shows you how accurate it is (we have a 6-speed). And, my wiring diagrams don't even
show the 3 ATEC fuses which are plainly present in my fuse block under the dash cover.
Roland, I would send the ECU and the touch pad to John, that way he can tell if it is one or the other.
I used the diagram I received from Richard Andrews to measure the voltage going to the shift pad. I have twelve volts between pin 1 and point 7 on the RSI connector. My display does not light up. Seems to me it should. May have a display problem not an ECU problem.
Will send my ECU to John Kopalek if I n believe I should. But right now I'm leaning to a bad shift pad. They don't give those away either but it's a bit less then an ECU. The new shift pad does not have a membrane it has switches and they have one in Benson. Just may go pick it up and see if I lick out. Really want to get back to Ajo.
Roland
OK I am out of the barrel, time for someone else to jump in. Replaced the shift pad and we are good to go. Was treated very well at Arizona Transmission in Tuscon. Got a break on the price of a new shift pad. We are under way and headed back too Ajo.
Roland
Are you coming here to Shadow Ridge or going up the hill? I'd like to see that heater you put in. Maybe someone will put LED lights in that barrel, gets scary after a while!
Shift pads don't look cheap on ebay. If you don't mind me asking, what were the damages?
Pierce
Will be interesting what Roland paid. I just looked on Ebay, and my #29507949 pad was $900+change! :facepalm:
I was charged $540.00 for the new style shift pad. This shift pad does not have the gel pad it has switches. Worked for me.
Roland
Not at shadow ridge. Not up the hill either. Found our own little spot.
Roland
Glad your going again👍. Now you can head on back to the outback in Ajo🌵😎.
Well done Roland. Congrats!
How about a photo of the new control panel? Not that I want one, you understand, but just for possible future reference...
Looks just like the original.
Roland
Good job Roland. Better the switch pad than something in the transmission.
So you said (earlier post) "This shift pad does not have the gel pad it has switches".
I'm not clear on what is different... Is it just the material surface on the "buttons"? Are these smooth plastic instead of the silicon rubber stuff? Does the button actually move when you push it, or does it just read the pressure? Just curious...
Actual micro switches under the pad. Otherwise looks the same, feel is different though.
Roland