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Topic: ABS light on (Read 638 times) previous topic - next topic

ABS light on

I have read prior threads, but I still would like some guidance...

While "in port," I recently replaced the exhaust system (resonator), rebuilt the six packs (bless that little kit!), Added helper springs to the brakes, and had a pack rat in the basement.  When I started the coach a few days ago, the ABS light was immediately on.

I can't see a reasonable way the exhaust work could cause the ABS fault.  Nor do I see a way the six pack rebuild could cause the problem, short of hacking an unrelated wire in two.

I could have damaged a wheel sensor wire while doing the helper springs, or my rat ate through a wire.  Or a totally unrelated failure with really suspect timing.  Am I reasonable so far?

So I look at it this way...

1.  Try to pull codes from the ABS controller module.  Short of good guidance from the trouble codes...

2.  Make sure the wheel sensors are in place.

3.  Clean the connections at the controller box.

4.  Look for chewed or frayed wires.

5.  Put black electrical tape over the indicator light and get back to life.

My retarder functions like it should.  It sounds like finding parts would be like getting struck by lightning.

Does this sound like the path?
Matt B
1998 u-320

Re: ABS light on

Reply #1 –
Matt,

Yes, good list, certainly through #4.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: ABS light on

Reply #2 –
Matt
Did the light go out after you moved the coach a few yards or did it stay on after driving it?
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: ABS light on

Reply #3 –
If you know that the retarder works then you've obviously driven it.  When we had trouble with our abs ( burnt sensor ) it told the Allison to lock out 5th and 6th gear and was even having trouble locking up 4th.    So,, I removed it.  The co. that made it is no longer supported. No parts. 
 
  I figured you would only use it in a sliding situation.  Slick pavement.  And we avoid driving in the rain and never in the snow. 
Robert and Susan
 1995 36' 280 WTBI 8.3 3060r
 1200 watts on the roof, 720 Ah of lithium's
 Build # 4637. Motorcade # 17599
        FMCA  # 451505
        18  Wrangler JLUR

Re: ABS light on

Reply #4 –
Quote from: FourTravelers –
Matt
Did the light go out after you moved the coach a few yards or did it stay on after driving it?
The light came on before the coach was moved.  I don't think it came on a couple of weeks ago, when the coach was backed slowly about 40 feet into its stall.  The light has not gone out.
Matt B
1998 u-320

Re: ABS light on

Reply #5 –
Quote from: Bob & Sue –
If you know that the retarder works then you've obviously driven it.  When we had trouble with our abs ( burnt sensor ) it told the Allison to lock out 5th and 6th gear and was even having trouble locking up 4th.    So,, I removed it.  The co. that made it is no longer supported. No parts. 
 
  I figured you would only use it in a sliding situation.  Slick pavement.  And we avoid driving in the rain and never in the snow. 
No gear lockouts.

We too avoid slick situations.  I suppose many of us would pump the brake anyway if we knew we were skidding.
Matt B
1998 u-320

Re: ABS light on

Reply #6 –
Next step...

I have opened the ABS box.  The Modal Power TK2 ABS manual says to touch the three pin diagnostic connector onto the two pin terminal to initiate the display of the codes.  There are no connectors in the box for these terminals.

I ASSUME that I can get the codes with the under dash button on the right.  Where is the indicator lamp?

The manual suggests that the codes must be removed manually.
Matt B
1998 u-320

Re: ABS light on

Reply #7 –
Moving ahead...

I set my phone to record, and sat it next to each wheel, while I disconnected and reconnected the self-test wires.  The driver front did not click like the rest.

Am I correct to assume this is a static test?  I assume that the sensor or the wiring from the sensor to the ABC controller is bad.  I can't see how this could test that the sensor is in place or correctly positioned.

Still interested in clearing the codes.
Matt B
1998 u-320

Re: ABS light on

Reply #8 –
After all your mods on the coach, did you drive the coach over 5 miles an hour? According to the trouble shooting guide, the light should go out after going over 5 MPH.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: ABS light on

Reply #9 –
Quote from: rbark –
After all your mods on the coach, did you drive the coach over 5 miles an hour? According to the trouble shooting guide, the light should go out after going over 5 MPH.

That is why I asked the same question, ours comes on occasionally when first starting the coach but goes out after driving it a short distance.  There was a time when it would stay on constantly a couple of years ago, a check with an ohmmeter showed the front passenger side to be defective. Found one online and replaced it........ light went out and has worked fine since.

 
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: ABS light on

Reply #10 –
Sensor proximity can cause the light. Probably got bumped when adding springs. Manual has the correct clearance.
1998 36' U295 Mechanical 8.3

Re: ABS light on

Reply #11 –
I did drive about 100 miles since the other work.

Would the sensor fail to alert if the clearance was incorrect?

If replacing the sensor would fix it, I will likely do that.  That is, if I can figure out how to clear the codes.  It looks like multiple sources still sell the wheel sensor.
Matt B
1998 u-320

Re: ABS light on

Reply #13 –
Quote from: Racedad –
ABS: Trouble Shooting - All Things Foretravel


The procedure for retrieving the codes is at least possible - the other two procedures I found were not so much.

Is anyone familiar with the code clearing process?  Is there a light I can't find?  The procedure says "indicator light" and then "ABS warning indicator lamp."  I would assume the second one is the "ABS" on the dash display.  Is there another light somewhere?

I tried the procedure to retrieve codes, but nothing changed.  The Internals of the ABS ECU shows a code, but I cannot get it to show if there are more codes.
Matt B
1998 u-320

Re: ABS light on

Reply #14 –
Quote from: oldmattb –
I did drive about 100 miles since the other work.

 It looks like multiple sources still sell the wheel sensor.

This is the one I used.....
Front ABS sensor - Haldex AL1027196
 
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: ABS light on

Reply #15 –
I don't think I have abs on this coach but I have owned a gang of semi's that did and while I'm a stickler for things to work as should, we have gone with #5 a number of times. I was applying brakes on large vehicles long before AB flippin S was invented and on some mighty slikery roads and I will wager I'm not the only one. Wish I could have been some help Matt but have rarely been able to help myself in this matter. ABS should have PIA as a last name imo.
Dub McBride 1996 270

Re: ABS light on

Reply #16 –
Matt, agree with Dub on doing #5. 
I spent a lot of time and $$$ when I first got the coach trying to get the ABS to work and the light to stay off. After all the hassle and two different shops working on it, the light would come back on in a short amount of time.
Finally, one small square of black tape, and ......"it's worked perfectly ever since".
It's been three years now and I haven't ever seen the need where I might have wanted or used the ABS.
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: ABS light on

Reply #17 –
Quote from: MarkC –
Matt, agree with Dub on doing #5. 
I spent a lot of time and $$$ when I first got the coach trying to get the ABS to work and the light to stay off. After all the hassle and two different shops working on it, the light would come back on in a short amount of time.
Finally, one small square of black tape, and ......"it's worked perfectly ever since".
It's been three years now and I haven't ever seen the need where I might have wanted or used the ABS.
Too funny. I was going to stay quiet about the subject, I do want to repair mine also. Last time I ran threw the self test I could hear it skip one axle. Will eventually return to resolve but I have a similar tape covering ABS light. Another piece 3/4 covering the Hi bean indicator also. Too busy chopping, no time to sharpen my axe.
Scott
 

Re: ABS light on

Reply #18 –
My plan at the moment is to try to repair the system.  I know that one sensor is not passing the self test.  If it is the wire, I suppose the break can be repaired.  If it is the sensor, they are inexpensive and available.  Beyond that...

I am surprised by the contradictory information for the system.  Apparently there are a variety of versions that work differently.  On some, the light for a properly functioning system extinguishes immediately, others a person has to drive for a bit.  Some self-test when the key is turned, others require a switch.  I have read that merely replacing a defective sensor does nothing, that it corrects operation but does not clear the codes, and that it clears the codes.  I have found three methods of displaying trouble codes, but none work on mine.  Even the manual I possess is so vague I still don't know if there is one indicator light or two.  Some sources indicate that a sensor code disables the system, other sources say the remaining wheels will still have ABS.

No wonder an inch of electrical tape is an accepted strategy!

Not complaining about you guys, just ruminating.
Matt B
1998 u-320