My VSS is fragging out which, of course, makes the ATEC system go into "Do Not Shift" mode. So I'm stuck on I-75 south on the shoulder just inches from the white line trying to get her going again. I'm in neutral. I reset the codes using my laptop an DLINK interface but no dice. Still flashing DNS. I also disconnected touchpad and waited a bit and reconnected it but that didn't do it. Can someone please tell me exactly where this Vehicle Speed Sensor is located? I need to address this.
If no help, try a Google on speed sensor location for your model transmission. Should be near trans output shaft, although some electronic trans may have two or three in same general area.
Thanks...I've done this a little without any definitive results that I could understand. Does anyone know of a way to force shift an ATEC trans just so I can get off the road? This is dangerous. I'm about to call a wrecker.
You should be able to get it in drive. It will not shift out of 1st, but you should be able to do 10 or 15 MPH to get you in a safer spot.
I agree with the speed sensor being the likely issue. It is a common failure. I think there are 2 sensors on the driver's side of the transmission and a local Allison dealer probably has them in stock. You will need to provide the transmission serial number. Once you get the sensor you can't screw up and put the new one where it does not belong because although they are near one another and look similar I think the plug or mounting method will keep you from putting in the wrong location. I think the speed sensor that might have gone bad is the one closest to the engine.
Not much help but if you cannot get the 700 series ATEC to go to limp mode I have no Idea how to made it engage,they are in their own world
Thanks for the thoughts. It is not in limp mode. It will not shift at all. Stuck in Neutral. I've tried everything. Going to get towed into a campground two miles down the road and will continue to troubleshoot. It gave me a speed sensor fault code just as it failed. I saw it on my dlink screen. And at the same time my speedo stopped working and the trans went into fault mode.
Remove and replace with a 740 with air shifter, for ease of retrofit...?
Someone had to type it...
Glad you got it cleanly off the road, and didn't meet the bear with fur...
happy coaching!
buswarrior
I see where someone on Facebook said to remove speed sensor and clean off end and reinstall. Did you try that?
First time ever getting towed into a campground. I could get used to this. Will get down and dirty tomorrow troubleshooting
You should be able to see the speed sensor on the side of the trans (should be a 2 wire most likely), there may be 2 or 3 of them. Yours is different from my B500 but on mine there is a sensor on the input turbine, one in the middle and on toward the tailshaft. Mine gave me all kinds of fits a few years ago until I finally found a break in a wire at the plug on the output speed sensor. Ohm the harness from the sensor to the tcm while moving the wires around to make sure its not a wiring issue. You can usually get the sensors next day at napa.
At least you are down South and not in snow or slush, or stuck in downtown Atlanta in the middle of traffic.
Quote from: thomasinnv on January 01, 2019, 03:39:53 PM
You should be able to see the speed sensor on the side of the trans (should be a 2 wire most likely), there may be 2 or 3 of them. Yours is different from my B500 but on mine there is a sensor on the input turbine, one in the middle and on toward the tailshaft. Mine gave me all kinds of fits a few years ago until I finally found a break in a wire at the plug on the output speed sensor. Ohm the harness from the sensor to the tcm while moving the wires around to make sure its not a wiring issue. You can usually get the sensors next day at napa.
Awesome. Good info here. Thank you. I'll dig around tomorrow in the light of day and see what I can find. I'm hoping to get this fixed before the end of the week.
a bad speed sensor shouldn't prevent engagement on the 700 if you have power to the pad and ECM it should go to the limp mode ,the pad is powered by a fuse in the upper corner in the panel under the drivers window,the ECM fuses are in the battery compartment on a MCI good luck
I hate that for you Scott. I am no help to you, but we are following along closely.
Davy
Problem Solved.
Found the speed sensor and followed the two wires to the harness where one of them was corroded and broke in half. I temporarily spliced it back in and the trans issue was gone. So I'm now properly splicing and soldering the connection so we don't have this issue in the future and we should be on our way before noon. Thanks to all who helped. The photo shows the wiring where it enters the harness. I had to peel and cut the harness shield (carefully) so as to get to the proper wires, that's why it looks like a rat chewed it up.
I see where the blue hose has worn through the outer covering of that multi wire cable. You should completely replace cable, or a good part of it, if it is lengthy. Then secure hose and cable to avoid rubbing.While you are at it, check back side of that hose, as it may be rubbed thin also.
Glad you got it up and running. Scott how many miles on your coach?
Glad you found the problem. The best way to get attention is to be towed into a camp ground or in our case come in on a low boy at Quartzsite to the GM rally, that gets every bodies attention and also gets you well known.
It always amazes me how people are able to find a "cracked or broken" wire in a multi strand cable like that.Not sure If I could do it myself.
Glad it was easy with a complete circuit a bad speed sensor will not shut the the 748 down
Good to know cliff. Thanks guys. Absolutely, we were the freak show as we were being towed in lol. Lots of people gathered.
Congrats! I would have probably spent 1000 bucks to watch a mechanic find that damn wire. ugh...i'm so mechanically bad.
Scott u are not worried about getting towed like that? Im told my 8 and your 9 has a hollow frame and can be bent if not towed on a flat bed
Quote from: Branderson on January 03, 2019, 05:03:40 PM
Scott u are not worried about getting towed like that? Im told my 8 and your 9 has a hollow frame and can be bent if not towed on a flat bed
Scott has been in all kinds of predicaments, his frame is just fine. If you put a raised coach on a flat bed, then you will have conflicts with bridges and trees. If a tow truck is equipped with long reach lifts for the front wheels, there is no stress on the frame that does not already occur while driving normally. You just have to pull the axles if going very far.
The C's are different type construction than a 8 or a 9 he is ok
Quote from: luvrbus on January 03, 2019, 08:03:31 PM
The C's are different type construction than a 8 or a 9 he is ok
ahh okay,
Would you agree with mine, I shouldn't tow like that due to the hollow frame?
Quote from: edvanland on January 02, 2019, 08:51:42 AM
Glad you found the problem. The best way to get attention is to be towed into a camp ground or in our case come in on a low boy at Quartzsite to the GM rally, that gets every bodies attention and also gets you well known.
Ed;
What was the eventual problem? fuel pump maybe?
Merle.
If I remember correctly, it was a problem with the directional valve on the fuel filter from the fuel tank and the electric fuel pump.
Quote from: edvanland on January 02, 2019, 08:51:42 AM
Glad you found the problem. The best way to get attention is to be towed into a camp ground or in our case come in on a low boy at Quartzsite to the GM rally, that gets every bodies attention and also gets you well known.
Just for you Ed, your buddy Dave :)
https://www.youtube.com/watch?v=XWhH4tgEjLc
I drove over to get Ed's bus running and I don't remember the cause of the problem but it was a very minor
Wasn't it the starter relay.
I remember i helped him get the new long belt on and adjusted.
And anyone that has seen Ed's Bus you have to remember if you are working on a Freightliner or an MCI, LOL
Sorry Ed could not resist... ;)
There are so many times when a bus & its owner gets bailed out when tapping on the accumulated knowledge of the board - I got to say Scott & Heather has done this sort of stuff several times and really take the prize in my book - kudos to Scott for reaching out, kudos to the board for spilling the beans & kudos to Scott again for the success. I just had to say that...
Lol. Thanks guys. We are rolling up soon on 9 years of fulltiming...over two different buses. It's an absolutely nuts lifestyle we are living with our two little girls, but it sure pays the bills nicely. And I love what I do...and my wife loves fulltiming...now if only I could learn to love my bus. It's not a love hate anymore...it's pretty much descended into a hate hate. I'm ready for a truck conversion.
A truck conversion isn't going to be trouble free either. You have to accept the fact that your bus has a lot of miles on it. I spent 10 years converting my bus, five of which were spent rebuilding everything mechanical before I did the interior. 10 years part time, as I was working to pay for everything.
Cliff it was the safety fuel shut off that was bad back at the engine. If I remember it you said it was so idiot bus drivers did not try to start the engine while it was running. You cut the wire to it and it has run fine ever since.
Hay Dave I did that so every body would get to know us and it worked. Thanks to you for helping me get that long belt on and to Cliff for finding out what was wrong with it.
We will hopefully see you in Quartzsite some where.
Geoff is correct in saying a truck conversion is not going to be trouble free-mainly because both a bus and big truck use the same drive train. What a truck will have is a far simpler electrical system, much easier to service, ANY big rig truck repair shop can work on it. The only really big negative is, no matter what you do to a truck, it won't ride as smoothly as a bus. But at this point, I'm ready for my truck to be done (hopefully by next summer).
On my cabover, I can tilt the cab and my radiator, engine and transmission are fully exposed. AND I only have to tilt the cab when major work has to be done on the engine (Allison transmission can be worked on from underneath). I can check my radiator, check engine and transmission oil, change my fuel filters, change my oil filter and water filter, change my oil, add engine oil and transmission oil without tilting the cab. I'm so looking forward to getting my truck done-unfortunately life has a way of getting in the way. Good Luck, TomC
Scott the next time it puts you on the side of the road, try pushing it with your tow car. I have had to do this twice over the years. One time about two blocks and another about 5 miles. If the ground is level it doesn't take much to move the bus.
Jack
It's been a while, now I remember the shut down was acting up from the safety system and talking to Ed on the phone how it worked and how to bypass it. Also the fuel filter valves. Anyway, everyone chipped in and saved me a trip to Quartzite. I'm not going to make it this year either.
Scott I don't know you well but I must say you expect a whole lot of your wonderful bus. Full timing for 9 years with your family & having wifey loving it too sounds like heaven from this end. If you've always tapped on the board for all your bus woes it hasn't or at least doesn't seem to have been that bad from my (our?) perspective. Unless you have a brand new rig under full warranty & even then murphy's law prevails. At any rate kudos for doing it yourself a keeping on keeping on. Ditto on using the toad to move the bus to safer ground we've done that on many occasion in almost 4 decades of bussin, From a 4 cyl VW to our 4x4 Sierra PU. Uphill, downhill, level, 1 block to 38 miles down I-10 out of fuel. Your tow was the clincher & IMHO you could have avoided that. I'm done (for now). ;)
Scott did the right thing by having it towed professionally. I have pushed vehicles with a four wheel drive, but it is only practical for short distances on quiet roads. He was stuck on the very edge of I75 in Georgia with traffic whizzing by, it would not have been safe to creep along the shoulder without (or even with) emergency lights. ???
Thanks guys...you're right, a truck will have problems too...but I can open the hood and deal with them. You know how far I had to crawl into the bowels of my hot engine bay to get to that sensor? Jacking up a truck to get to its underparts is way less drama too.
I honestly have loved full-timing...and we have averaged 15,000 miles a year in our coach which is more than a good chunk of people on this forum so I know I'm slated to have more issues than some of you guys. You are ALWAYS on hand ready to help us and we are forever grateful. As for moving the coach with our toad...I also have done this before and I know it can be done. My toad is a 2015 Extended Length Ford Expedition 4x4 with the 365hp ecoboost It could do it, but as others have said, I-75 was nuts that day...the cop that closed a lane of traffic so we could get into the lane was nearly T-boned right there in front of me...the shoulder was not wide enough to stay off the hwy lanes especially where there was a guardrail...I just couldn't risk putting my wife back there while I navigated the bus and she wouldn't have wanted to drive the bus with me pushing. I have tow insurance and the tow cost me $0. It arrived and had me hooked within 1 hour and another 10 minutes later, we were safely parked in a nice little campground near the hwy. It honestly was the best stranding we've had to date. No complaints.
I absolutely agree that the truck will be easier to service - flop the hood open and 3/4 of the noisy things are right there in front of you. The other big advantage is that truck shops are everywhere along the highway. You pull into a Freightliner shop and they'll recognize most of the rotating bits, even if the badge on the grill doesn't say Freightliner. Similarly if you pull into an International shop they'll understand your Freightliner or Pete. That is simply not true when you pull your bus into any truck shop.
Scott, it is true that more miles each year brings more maintenance costs, but exercising our buses each week instead of 4-6 times a year may save us some of the heartaches that others experience because of lack of use. I usually move every Saturday and occasionally I will be in one location for two weeks. Although I do have bus problems and I do pull my hair out over them, most trips are completely trouble free and smooth.🙌🏼 🙏🏼
Davy