Tractor ABS?

[Ozbozz57]

Hi guys,
I'm about 1200 miles in on a trip from NW WA to the Southwest.

'05 Freightliner/Thomas, MBE 906, Allison 2000, air brakes.

Stopped in Tonopah NV for a break; headed south on US95, noticed upon departure:

"TRACTOR ABS" light on dash panel.

A few miles down the road, saw trans temp elevated, 200° F, then 220°F, went as high as 250°F. (on the stock gauges, interpolating best I can)
I'm pulling a Suzuki Vitara toad, 4 down. Done it many times before, no issues.

Engine rpms are higher than normal at indicated road speed - normally 1800 @ 52 mph, now 2100 @ 52.

It seems like the trans lockup function isn't working.
Is that possibly heating up the fluid and giving me higher rpms?
And does it seem related to the "TRACTOR ABS" light?
(happened at the same time)

Engine sounds and runs fine; water temp normal, 180-190 ish; no unusual sounds, brakes working fine, near as I can tell (no change).

Suggestions?

 

[Timeline]

I'd check for a hanging brake... that's a wild guess but have seen it before. Sorry your having trouble, good luck!

 

[Ozbozz57]

Timeline, thanks for the response. Do you mean a brake shoe dragging? I just felt the drums, none felt hot, but I've been parked now for 2 hours. This cropped up after I had parked with the rear brakes locked. (always park that way) How does that relate to the "tractor abs" indication on the dash panel?

I noticed, looking under the bus, that the left rear air brake actuator is oily. The right one is not, just dusty. I don't remember it looking like that. Also looks like some oil has been flung on the inside of the left inner tire. I don't remember seeing that, either.

 

[PorchDog]

Just a cursory google search -- there is a "tractor ABS" and apparently a "trailer ABS" light -- for a truck tractor / semi trailer type setup. There was some mention of a switch underneath the dash to make the light or some display display the actual fault codes.

As mentioned above-- maybe a dragging brake, or brake light application stuck on. I am not familiar with these transmissions-- but on light duty stuff -- if you touch the brakes it unlocks the torque converter.-- So-- if you have a stuck brake light switch-- it might set an ABS code, and disable the torque converter. Just thinking out loud.

 

[Ozbozz57]

Thanks, Porchdog. Good stuff to check.

 

[cadillackid]

the transmission temp... watch your tach and see if it varies alot as you give the go pedal light up and down while on the highway.. almost sounds like the computer disabled lockup on the transmission for some reason.. only time i generally see this is if the datalink between engine and trans dies.. it woud however turn on a check trans light typically.. maybe it happens for some reason if the ABS goes down? seems wierd...

 

[Ozbozz57]

Thanks, Cadillac. I dug around in my electronic Freightliner school bus chassis manual, and eventually found the dash codes that were displayed. MID 136, SID 013, FMI 06.
Retarder shorted to ground.
I limped the bus into Las Vegas last night, and it's now at the Freightliner service center.
Yes, the engine RPMs seem too high for the road speed, as if torque converter lock up is not happening. They just took the bus back into their shop area, so hopefully I'll be back on the road today. Heading to Casa Grande AZ.

 

[Ozbozz57]

No answer yet

The Freightliner service Center here in Las Vegas hasn't been able to figure out what is wrong so far today. SVC mgr says they have to email somewhere, and that I can take it outside the gate, sleep in it, then bring it back in tomorrow morning.
The codes say it's retarder circuit shorted to ground. This vehicle hasn't a retarder.
Maybe I'll figure it out, once they give it back to me. It's a quarter to three, I've been here since 5:30 this morning.

 

[cadillackid]

I was looking back at my International notes which are not freightliner of course but the standard is Module ID 136 is an ABS module.. when I looked up bendix ABS codes , 13 is a wheel speed sensor with a circuit error such as a short or open...


that would kind of coincide with the ABS light being on..
a retarder fail code would sort of coincide with no lockup.. however the allison itself isnt triggering its check trans light...


something just seems off here.. maybe they could try running the ABS module diagnostic software itself and see if it comes back with anything.. just for kicks as i call it..


when I googled the code it also seemed to reference ABS related issues...

 

[PorchDog]

Yes. If you lose a wheel speed sensor signal-- bad sensor, broken wire, etc. -- it can cause all kinds of ABS issues. BUT-- I would think it would be fine to drive-- just no ABS.

I googled retarder last night, and it keeps talking about a retarder relay, and the associated wiring-- so with no retarder-- and no converter lockup-- this makes no sense to me.

 

[cadillackid]

Yes. If you lose a wheel speed sensor signal-- bad sensor, broken wire, etc. -- it can cause all kinds of ABS issues. BUT-- I would think it would be fine to drive-- just no ABS.

I googled retarder last night, and it keeps talking about a retarder relay, and the associated wiring-- so with no retarder-- and no converter lockup-- this makes no sense to me.

if the code were coming from the allison TCM it could be an input wire shorted to ground.. its possible that the wiring was installed and left to hang someplace thsat got wet , chaffed, etc. some of these vehivles the wiring for various items is installed even if the option isnt installed.. according to my allison troubleshooting stuff though its suppose to turn on the check trans light...



on some vehicles the ABS module provides the speed data to the ECM so the dash speedo woud break if the ABS were dead.. seems wierd that a nABS code would disable lockup... seems counterintuitive.. you get better more even braking with lockup on, not off...



just have to wait and see what the freightshaker guys shake out of this one

 

[PorchDog]

Hopefully not too much $$$$$$.

 

[Ozbozz57]

Freightliner service manager late yesterday afternoon said they were going to replace the ABS module. WABCO.

You guys are really awesome. Thank you so much for your efforts and expertise.

It absolutely is too much $$$$$$.

My Freightliner FS 65 School Bus chassis manual says the code points to retarder circuit grounded. It has information on ABS air brake systems D-Basic and Advanced. I'm assuming my bus just has Basic - though those failure codes lead to the same conclusion on both charts.

It makes perfect sense that the wiring for such a thing could be installed in the factory wiring harness, even though no retarder exists on this particular bus.

Digression - Years ago I had a '99 Chevy Blazer that had an open drive line speed sensor failure that caused the ABS to make the transmission not shift above first gear. I had a Chilton's manual and was stumped, outside a lumber yard in Springfield OR. I asked the *universe" for help.

THE WIND flipped the book to the page that had the info on the ABS sensors. I hadn't been thinking about the ABS at all. I had a voltmeter with me, but I had no idea what values I should be looking for on these sensors. But I figured they should be some ohm value, neither shorted nor open. The driveline sensor was open. I limped it to a nearby AutoZone, and they had the part on the shelf. And they loaned me a big enough crescent wrench to replace it. That's when I learned that ABS can cause a lot of problems in your vehicle.
End of digression.

Of course by the time Svc Mgr delivered the "news" yesterday the next day shipping cut off time had passed, so it's Next Day air from TODAY. Arrives hopefully Friday, and Freightshaker installs it quickly.

Service manager says they have 6 hours in it. At $243 an hour.
Estimate $2900 and change.

Jerry (my dog) and I are "camping" outside their compound gate. A most unattractive industrial section of North Las Vegas.

Once they take your vehicle back into the bowels of a place like this, you're like someone waiting outside of surgery in a hospital for the "news".

Im going to go ahead and just let them fix this. It's a lot of money, but it will just sit on my credit card for a few days. Fortunately, I have the money in the bank to pay for this.

I will let you know how this all freightshakes out.

-Ross, 1200 miles from Bellingham WA.

 

[PorchDog]

At $243 an hour-- it does not take long.

Westinghouse invented the air brake for trains in 1869.

Westinghouse Air Brake Company. WABCO

As bad as this is-- I think the full hydraulic version of this is much worse.

Keep us posted.

 

[cadillackid]

At $243 an hour-- it does not take long.

Westinghouse invented the air brake for trains in 1869.

Westinghouse Air Brake Company. WABCO

As bad as this is-- I think the full hydraulic version of this is much worse.

Keep us posted.

there are WABCO ABS controllers and also WABCO full hydraulic brake controllers.. WABCO makes some of the air brake ABS units (as does Bendix and I thunk HALDEX)...



the WABCO full hydraulic brake control system is the one thats a royal PITA.. the main reason being WABCO offers very few service parts... most anything wrong with it results in a "replace unit" in the diagnostic tree..



ABS controllers are much the same.., I suspect ecause these unts have the ability to control the braking.. and these companies want to limit liability from offering service or rebuild kits that would undoubtedly at some point get installed incorrectly by a service tech and result in a crash...

 

[Ozbozz57]

Third day camped at Freightliner.

I'm going to try to describe what it is I've been told. Wabco sent the right abs module. But they apparently didn't send the right file to program it with. The servicer is trying to get the right program. Disappointment and frustration seem like awfully weak words to describe how I'm feeling.

 

[PorchDog]

You would think these programming files would come via an internet download.

On light duty stuff, we hook a PC via an interface adapter to the port on the vehicle and download the software. Must be different in the Heavy Duty world.

I assume all the modules--- ECM/TCM/ABS Module are all on the same bus, so now you wonder if there is a bus issue? If their scan tool can see/talk to all the modules-- that should rule that out.

Programming modules can be an exercise in patience for everyone involved.

Hang in there. This too shall pass.

Being broken down on the road is not fun.

 

[Ozbozz57]

Would any of you have the file? Or know where I could source it?

 

[Ozbozz57]

This module looks awfully dusty to be a new one.
The second photo was what my camera did with the barcode on the wabco module.
I'm guessing they must have taken the new one back out, and reinstalled my old one.
I hope they're not just selling me a bill of goods, and not really putting in any new part.

 

[Ozbozz57]

What if I just unplug the module? I don't care about having ABS brakes, I just want my transmission to work right.