ABS and ATC dash lights on

[Don White]

Happy Monday!

I took my coach out on Friday to exercise it after sitting for a couple months.  As I was returning to the campground both the ABS and ATC dash lights came on.  When they came on I was doing no more than 10 mph and applying the brakes to slow down for a tight curve to enter the campground I 'am staying at.  I let the coach sit over the weekend before starting it this morning.  Both lights came on and stay on.

Approximately 8 months ago while driving the coach I had to slow down rapidly to avoid a car that pulled out in front of me.  Both the ABS and ATC lights came on but went off after a few minutes.

I checked Coach Assist and didn't see any documentation on the ABS or ATC systems.

Does anyone know what these systems look like and their location?  I would like to at least give them a visual inspection before trying to find a shop to take the coach to.

Any other thoughts would be appreciated.

The coach is a 06 Marquis with a Roadmaster chassis.

Thanks.

[Eric Maclean]

This thread may help shed some light on your issues

https://beaveramb.org/forum/index.php/topic,10793.msg73347.html#msg73347

I suggest checking / setting the sensor air gaps on all the wheels ( most commonly drove axle or tag axle out of adjustment)
Once the sensors have be taped back in the system should reset and the light will go out when the vehicle reaches a speed of 20 mph.


Eric

[Scott Shearer]

Don,

We had an intermittent ABS/ATC light, the culprit turned out to be a dirty ABS test button. The ABS test button is under the removable dash cover next to the J1939 data port (see Section 9, page 277 in your owner’s manual). You could ‘feel’ that the test button was gritty when pressed, I cleaned it with tuner cleaner, no more ABS light issue.

-Scott

[Don White]

I located the ABS switch underneath the removable dash panel.  There is also a black switch that is not identified in my owner's manual.  Any thoughts?

[Scott Shearer]

The 2006 Marquis owner’s manual identifies the black rocker switch as an optional ‘ADC Test Switch’. I don’t see anywhere in the manual that explains what it is used for, it’s not referenced at all in the owner’s manual for our 2006 Patriot Thunder.

[Eric Maclean]

There are two major ABS ( traction control systems on the market I'm not sure which one was used on the Beaver products .
I have included links to both for troubleshooting.

As I stated earlier the most common problem with either one of these systems is sensor air gap too wide this happens because the wheel bearings allow the hub to move and push the sensors back in their retainer the retainers have a spring collar to allow them to be moved in or out,  when adjusting the sensors simply tap them in until they contact the tone wheel on the hub from there the wheel movement will push them back to gain the needed clearance there's no need to set a clearance .
If the sensor on a particular wheel keeps going out of adjustment it is indicative of wheel bearings that are out of adjustment allowing the hub to travel in and out on the axle pushing the sensor out of adjustment.


These short videos and manuals will give you enough to identify the systems and start diagnostics

BENDIX ABS

https://youtu.be/Kz1SvOeFR8s?si=NmFTva7HGa5t4A2u

https://atelierjp.ca/wp-content/uploads/2016/07/Manuel-dentretien-ABS-Camion-EC-60-BENDIX.pdf

WABCO ABS

https://youtu.be/euD4P1JumaM?si=E3j1tsqbzS1tFd8U


https://www.wabco-customercentre.com/catalog/docs/mm0112_web_en.pdf


Hope this helps
Eric

[Don White]

I was able to get under the coach today.  I believe I identified the sensor wire going into each of the axel housings. steering, drive, and tag.  What is unclear to me is how I gain access to the sensor to tap it back into place. 

Thoughts or suggestions?

[Eric Maclean]

Don
That is the sensor with the wires coming out the end of it , if you use a punch and a hammer a light tap should be all that's needed to move it in
Tap on the edge of the collar where the wires go in not the wires it will only move at most 3/16 of an inch.
It shouldn't take to much force to make them move however if the mounts are very rusty  the sensors may be seized in the housings and won't move it sometimes can require dismantling of the brake and hub assembly to gain access in this case removal unfortunately destroys the sensor which means replacing with a new sensor.

After looking at your pictures again it appears they are drum brakes in which case those sensors are likely mounted to the axle on the hub side of the brake spider which may require the brake drum removal to gain access
In this case it's best to retrieve the abs codes to determine which sensor is the problem.

Eric

[Don White]

Eric,

This is very, very helpful information.  The front and drive axels are disk.  The tag axel is a drum brake.

Thanks again.

[Don White]

Hi Eric,

I followed your directions and it has solved the problem.  I ran the coach down to the central FL area recently to get out of the way of Debby and then returned back to the FL panhandle several days later.  Total of around 500 miles without the ABS and ATC light coming on.

Thanks

[Eric Maclean]

Thanks Don for the update.
I'm glad to see that you have got it up and working properly.

Eric